JiaEn

The Bacteria Paradox Every now and then, an idea trends in the reefing community, and holds captive the mind of reefers. From ULNS, to ICP, to bacteria. Nowadays, it seems that the first course of action to any reefing issues is: add more bacteria. It helps especially when different vendors waxed lyrical about the efficacy of their bacteria products. From rapidly remove nitrate and phosphate, to instant cycling, to prevent the growth of algae. To us consumers, these magic in the bottle has so much appeal, especially with a whole lot of scientific sounding jargons (chemoheterotrophe, anyone?). However, does bacteria product work? Or rather, how does bacteria product supposed to work? Let me attempt to address this Pandora's box. The Niche which is Our Reef The aquarium we keep is practically an enclosed ecosystem. With it, comes the limitations. Just as there is a limit of how much fish and corals could be reasonably packed into the aquarium, there are limitations for the bacteria as well. There is a limit of surface for the bacteria to colonize. There is a limit of nutrients for the bacteria to multiply. There is also a limit of available oxygen to support their biological functions. Put it simply, an aquarium can only support so much bacteria. When they run of of oxygen, they die and foul up the tank. When they run out of nutrients, they die and foul up the tank. When they run out of space, they disperses in to the water column, causing cloudiness. The Massive Bacteria Being relatively simple organisms, bacteria takes over available resources rapidly. If left unchecked, they can double in number every few hours, within days, there will be more bacteria than the volume of the whole aquarium. Luckily, the limit of space, nutrients and oxygen prevent this disaster from happening. However, it is safe to say that the bacteria population in the aquarium is generally at the state of saturation: they take up all available surfaces, use up all nutrients and oxygen accessible to them. If this is true, what happens when we add more bacteria from a bottle? Let's get the ugly out of the way first. If the bacteria in the bottle is not viable, they will simply break down and join the nutrition cycle as waste. Not a good idea. How about viable bacteria then? To Challenge the Status Quo When a population of viable bacteria is introduce to our reef, the residential population is challenged. Remember, the aquarium is at capacity with the exisiting bacteria, unable to support the new addition. As the result, some bacteria will have to die. Those may come from the newly added bacteria, or from the exisiting population in the aquarium. Therefore, adding bacteria does not increase the population for nutrient cycles, unlikely to make a huge impact on the dynamics of an aquarium. But wait! What if the bacteria product adds in a special strain of bacteria, carefully chosen to be adaptable and hungry for nitrates? Wouldn't this shift the composition of bacteria population? More workers, less slackers. This must be good, right? Unfortunately, no. The aquarium is likely to harbor all these different strains of bacteria since the beginning. The reasons that some of these bacteria does not flourish in the aquarium is because the environment is not conducive for them. Perhaps the wrong pH, perhaps the wrong nutrients. Either way, the newly added, hard-working bacteria will unlikely be able to compete with the other strains in the aquarium and effect the desired change. Put it simply, the population and composition of the bacteria in our aquarium depends mostly on the state of our reef system. It's unlikely for bacteria products to change this equilibrium.

The Weakest Link What is the secret to good looking fishes and brightly colored corals? This is one question all reefers would like an answer to. True enough, numerous products promises to produce deep florescent metallic glowing intense colors with accelerated growth and extremely polyp extension . Something like that. Unfortunately, my experience tells me, such products does not necessarily help me to get the effect I need. Let me explain why. A Cinematic Experience I still remember an experience I had when I was in sec 3. For some reason, the school released us early. I decided to go and watch a movie with my friend. Back then, week day tickets are cheap. There were also promotions for large coke and popcorns. Everything one needs for a great movie experience, right? Turns out it was horrible. There were few patrons on a weekday, and the air-con becomes exceedingly cold. I spent most of the time wondering when the movie will end, so that I can return to the warmth outside. The rest of the time? Struggling about if I should take another sip of the icy cold drink, and tahan the shivering after. The movie is not important, the drink is not important, the friend sitting beside is not important, because a basic need of warmth is not met. The experience is determined by the weakest link. This is the same for the reef. At the end of the day, it is not about finding a better light, or adding a better supplement. It should be about identifying what is the weakest link in the reef system, and spend our limited resources where it counts. How to: Upgrades Granted, it is not always easy to identify the weakest link in our own reef. What we can do, however, is to ensure that we do not blindly spend money on upgrades Before pouring differnt color enhancing potions in to your aquarium, or buy the latest and greatest light and wavemakers, ask yourself this question. Are my corals healthy enough to take advantage of this?

I'm using a hybrid between zeovit and zeolight. Between the bacto reefball and automatic zeo reactor, the compulsory maintenance is less. It can probably auto pilot (go without feeding) for a few days. Any longer, probably have to switch out some product. Since my daily maintenance is basically feeding the corals, I can probably switch to redsea ab+ for coral food in a pinch.

Phosphate 0 by Hanna, Nitrate 1 ppm salifert. Pretty consistent. When I had bare bottom last time, I did not run zeolite based system. So need to use phos media to keep the phosphate down. Now there is no need for those. Nice look! But I want the right side to remain open and uncluttered. I feel the negative space is essential. My wall corals were mounted on the left side. In any case, the magetic attachment won't work for me because the tank is flush with the wall behind it. Thanks for the suggestion though.

The corals glue on the back wall dropped two weeks back. Probably not a good idea. They are on the sand bed now, since no more space on the rock work. Oh well.

Unintended Consequences One type question often asked by new reefers is "what should I do when.... ". These questions are often answered by suggestions of adding a certain product, equipment or organism. Sometimes, perhaps some techniques are recommend. While these answers may alleviate the immediate problem, it is probably not the most essential question for a reefer to progress. You see, the reef is a complex system. For any complex system, the interdependence of different factors is the central theme. When we attempt to adjust a certain aspect of our reef, be it feeding the corals, getting rid of cyanos, or supplementing major elements, we do not effect change only on that aspect. There are, almost certainly, other factors which will be altered. In some cases, a cascade of events may take place, and drive the reef system into a completely different direction. It's easy to know what a product or technique supposed to achieve. Afterall, that's plastered on the product packaging. But the key question we need to ask is: What are the unintended consequences of using it? I believe just by considering this question, one immediately become a more conscientious reefer. A Cyano Story It's with regularity that discussion of pest bacteria/algae appears on reefing platforms. In deed, these unsightly algae not only detracts from the beautiful reef aquascape, but also smother, poison, and other wise kill out precious coral. Such evil should be banished now! So the reefer seeks out solutions, one of the highly recommend product is cyanoclean. Reef safe, kills cyano, why not. The reefer added this to the aquarium. Bam. No more cyanobacteria, all is well...or is it? Although "reef safe", cyanoclean is a antibiotic, and it does kills bacteria. Although the biofilter will not be completely wiped out. Some of the bacteria are killed. These bacteria breakdown and release their bound nutrient into water. At the same time, the aquarium also have a reduced capacity to breakdown and reduce excess nutrients. The removal of cyanobacteria creates a void in the reef ecology, space and nutrients become available and untapped. Since nature abhors vacuum, these available niche is quickly filled by other organisms. Sometimes, to our dismay, dino flourishes instead. This is not an actual case study. However, events like this do happen fairly often. Many times, dispite our best intentions and hardwork, we may adversely impact our reef system. In order to solve an immediate small problem, we end up creating a bigger problem down the line. So, start asking the important question: What are the unintended consequences?

Thank you, I'm just trying to write my experiences down. I'm a chemical engineer by training, so that's that. By and large no issues. It's not a 100% replacement. Although calcium and kh are added at the correct ratio, the amount of magnesium supplemented is a bit... Random. Different corals will consume ca/mg at a different rate. So there will be a small deviation in the long run. But frankly, I would be more worried about the amount of trace elements added than the imbalance of major elements. So far I just need to check my Ca and Mg once a month, then adjust as needed. The acceptable range for these two elements are quite wide.

Major Balancing Act After sorting out the flow and light, getting nutrients balanced well, coral will start to grow, fast. When they do, they start to take up elements from water to build their aragonite skeleton. As the result, ions such as calcium, magnesium, strontium ans carbonate are removed from water column. At the same time, other major ions such as sodium, chloride and sulfate are largely untouched. If the consumed ions are not replenished, disaster can happen. The corals will start to run out of reef building minerals, and struggle with their biological functions. The depletion of bicarbonate ions from the water greatly reduces the buffering capacity of the water. This inevitably introduces pH related problems. On the other hand, it we add in unconsumed ions, the ion balance starts to shift. This is not immediately detrimental, but it does defeat the purpose of using a properly formulated salt. This leaves us with a challenging task. We need to selectively increase the removed ions, without adding in any more unconsumed ones. Supplementing the Consumption Aquarists developed various ways to cope with the challenge of supplementing major elements. Varied complexity, varied costs, varied unintended consequences for the reef. 1. Water change: by changing some of the aquarium water with newly mixed water, some elements are replenished. However, unless the element concentration for the salt mix is much higher, the supplement effect is weak. (Remember, when you take out the tank water, you removed some of those elements too.) 2. Kalkwasser: by dissolving calcium hydroxide to saturation in the top up water, then dripping of it into the aquarium supplements calcium and bicarbonate at the correct ratio. It's not with out limitations though. The amount added is limited by the evaporation rate of the aquarium. It does not supplement magnesium and strontium. It also have a side effects of raising pH, which may be welcomed in some aquarium. 3. Calcium reactor: I have not use it before in my aquarium, but I believe a properly setup calcium reactor will be the cheapest way to support element consumption in the long run. By using natural coral skeletons, or reputable media, all the important elements are supplement according to the consumption by the coral. The only down side is the space requirement as well as the low pH effluent, which can drive the pH of the aquarium low. 3. 2 Parts/3 Parts : Basic 2 parts dosing uses calcium chloride and sodium bicarbonate. A better version replace some of bicarbonate with sodium carbonate. This will negate the pH dropping effect of the bicarbonate salt. Another improvement to the formula is the addition of magnesium chloride / magnesium sulfate mixture. This not only top up the missing magnesium, but also keep the ratio of chloride to sulfate in the aquarium consistent. If you are sharp eyed, you may have spotted the challenge here. Although chloride and sulfate are added in the correct ratio, the aquarium water is not short of these ions. Although two ion balance is maintained, overall ionic balance is disrupted. Don't forget that a large amount of sodium is also added in the process. 4. Balling: Full balling supplements major element dosing with sodium chloride free salt. When use correctly, the balling dosing does not impact ionic balance. However, true balling products are limited. 5.Calcium Formate/Acetate: these organic salt of calcium can dissolve in rodi water to form fairly concentrated solution. When added into the aquarium, they act as a mild form of carbon dosing, and break down into calcium and bicarbonate ions. The ionic balance of the water is unaffected. If the microbial population of the aquarium is in disarray, it is possible for such supplements to fuel the growth of cyano or dino. Just like what happens when carbon dosing is over aggressive. I would like to maintain good ionic balance for my aquarium, therefore I use this method of supplement. Using all-for-reef, the need of the aquarium is taken care of with one single head dosing pump.

Picture updates. FTS and main rock-scape. The corals are doing ok. The color should be better in a month or two. (Hopefully). The PAR at the highest part of the rock is insane. So some corals are struggling to adapt. Those settled down and adapted, have beautiful florescent colors. Current element consumption at 45ml of all-for-reef per day. So glad that the powder product is available.

The Dilemma of Sandbed My first setup was bare bottom. I went with this because I wanted a low maintenance tank. It was low maintenance indeed. Any waste and detritus gets pooled into neat little piles where the deadspots are. It is easy to vacuum them out when(if) I decided to do maintenance. Bare bottom tanks have its short comings though. Firstly, the reflective bottom glass is rather unattractive. Sure, once the coraline algae started to grow, it gets a bit better. However, personally, I feel an aquarium is unbalanced without substrate, and thus incomplete. Secondly, lack of sandbed precludes me from keeping sand dwelling animals well. Halichoeres and Anampses wrasses are both beautiful and functional in a reef aquarium. They do best with a sand bed. I did managed to keep a melanurus wrasse long term in the bare bottom setup, but seeing it sleeping in detritus is ... unpleasant at least. Lastly. In a bare bottom setup, detritus, loose bits of rock, and tiny broken frags sticks out like an eye sore. The contrast is just too great. Overall, the bottom feels cluttered and dirty, even though they are reasonably clean. I switched to a setup with a shallow sand bed. Sandbed : the Credit Card of the Reef Sands bury many sins. Detritus are trapped away, the aquasacape looks balanced (it's ironic really, most of the SPS corals I have seen during diving are nowhere near a sandbed) and my wrasses finally have a place to sleep. However, burying the problem does not make the problem go away. The trouble, which is now out of sight, continue to brew. This is like taking up and credit card and spending beyond the means. The money is still owed to the bank, and the interest grows. As more and more matters are trapped jn the sand bed, the dynamics of the sandbed also changes. Bacteria grow explosively to take advantage of these available nutrients, and potentially depleting the oxygen level in the sandbed. For a deeper and undisturbed sandbed, the low flow and bacteria action can cause anaerobic/anoxic regions in the depth, production toxic hydrogen sulfide gas. This may take a few month to a few years dependig on how the aquarium is run. In a way, it is like accumulating hefty credit card debt, one has to put in so much effort just to stay afloat. If the above sand bed is disturbed. Disaster happens. Not only the accumulated detritus and hydrogen sulfide are released into water column (bad), the anaerobic bacteria also perish when exposed to oxygen rich water (bad). This sudden disruption can easily trigger a crash event. Sometimes, all it takes is to shift a piece of rock. This is not unlike when credit card payment is defaulted, the bank and repo man will come. What I'm trying to say is, sand bed needs tender loving care. The lack of maintenance today, maybe the cause of disaster down the road. Keeping a Good Sandbed I started with clean up crews, hoping an army of janitors can keep the sandbed clean. Nassaurius, cerith, sea cucumber, conches, and hermit crabs. More than 100 CUC were added into the aquarium. They did a fine job to turn over the sand, and even eat a bit of the detritus and algae. The sand bed looks clean. However when I take the turkey baster to blow at a spot of diatom on the sandbed. What I saw changes my mind. I believe a sustainable, safe sand bed needs a lot of maintenance. Such maintenance is irrespective of how the outward appearance of the sandbed itself. Even for a pristine sandbed, a simple turkey pasting will reveal so much trapped matters. (If you want to try this, and have not clean the sandbed for quite a while, please only do it for a small corner). There are reefers who enjoys tank maintenance, scraping algae, and water change. I'm not one of them. I feel that maintenance work are chores, the less the better. Even so, I will use a turkey baster to jet the entire sand bed every other day. The detritus flushed out either to be captured by corals, or caught in floss to be removed. Some lives in sand bed, such as bristle worms, are brought up to the surface, their population are controlled by wrasses and file fish. Those fishes follows the turkey baster, and picks up any worms and pods uncovered by jetting. There you have it, keeping the sand bed like a responsible credit card user: pay the debts on time.

Feeding the Unseen The last link in the chain of feeding is to take care of the tiniest live forms in the aquarium. Bacteria, phytoplankton and zooplanktons, as well as tiny pods and worms. For the sake of simplicity, I call them microorganisms (Some of them can be quite big). These microorganisms are the foundation of the food web, and their presence is essential to ensure waste are rapidly removed or recycled. Pods and worms are instrumental in feeding on detritus, further breaking them down and fixing some of the nutrients in their biomass. Phytoplankton make use of the dissolved nutrient in the water, again fixing some of them in their biomass. Bacteria... Oh well, what can we do without them. These tiny organisms in turn feed the corals and fishes, thus the nutrients are recycled within the system. Trash to treasure. Keeping the Unseen Alive Just as we feed the coral and fishes, we cannot expect to keep the microorganisms alive without giving them adequate food source. And just like a starved yellow tang, those micro organism will waste away if the source of food dries up. When that happens, they die. No only do they stop working, they also releasing all the fixed nutrients back into the aquarium. Why does nutrient spike some times when we cut down feeding? One of the possible reason is that microorganisms die. Why does cyano or dino takes over the aquarium, or SPS have tissue necrosis? Disruption to these micro organisms is the suspect. Why does newly set-up aquarium takes time to mature? It's because these organisms takes time to grow and stablize in numbers. The bottom line is, with modern techniques, it's no longer a challenge to keep water parameters at any desired level. However, keeping the army of microorganisms in their delicate equilibrium, that's a challenge and an art. Especially since this is something we can't see or measure easily. Biofiltration These microorganisms, which is part of the biofiltration, builds up slowly, and can be disrupted quickly. There are several implications: 1. These part of the aquarium is not something which can be turned on and off at will. Unlike a skimmer, or a gfo reactor, even if we don't need the export capacity, we still need to keep them running. 2. Reef safe medications may destroy part of this group of microorganisms, without us noticing. This could explain why some reefers faced issues with some products. 3. When these microorganisms grow and multiply, the demand on nutrients will grow as well. That's why some established reef aquarium requires intense feeding, so much so that if the feeding is dialed back, the aquarium responds negatively. That's it. My piece on Nutrients in the reef.

On a different note, I have a (untestes) hypothesis about how instability impacts sps. I believe the fluctuations in nutrient does not impact the sps itself. Rather, the instability of the available nutrients cause a shift/collapse of the bacteria holobiont in the coral mucus. The disruption of the existing bacteria population gives opportunity for pathogenic bacteria, such as vibrio sp. to thrive and cause the decline of sps. In a way this also explains why the impact of the parameter shock is rarely immediate, but often has a lag time of a day or two.

I think it's safe to say that LPS has more elaborate prey catching mechanism as compared to sps (actually, it's an assumption as well ) so being less dependent on photosynthetic symbiosis, they are less affected by nitrate and phosphate levels. What is low and what is high? We need to have some basis to have meaningful discussion. We also need to consider which element is limiting in the particular reef. Can we say a low nutrient is less than natural reef level, normal nutrient is average of reef crest level, moderate nutrient is perhaps double that.. Etc. This can make further discussion more consistent. I feel that the abundance of prey meets their nutrition needs

Ah sure! Then this thread will be more focused too.

Add-on to previous post: I would like to qualify the idea of "feeding the fishes is feeding the corals" On one hand, I fully agree that sufficient nutrient input to the reef aquarium is beneficial to both fishes and corals. However I find it presumptious to conclude that corals feeds directly from left over food from chewing or fish poop. Corals polyps have a mouth which is evolved to ingest planktons of a certain size. Therefore, it's a leap of faith to suggest that the poop of the fishes coincidentally falls within that size range to be captured by corals. What I think is more likely to happen, is that the nutrients from the breaking down of these organic compounds helps the bacteria flocks to grow. Or perhaps some of these are incorporated into the coral mucus, which helps the growth of the mucus holobiont. Either way, I don't think coral eats fish poop. Am I making sense? If anyone is familar with this topic, please join the discussion and shed more light on this.

The Trappers Another group of livestock which requires feeding are the sessile organisms. Corals, clams and some worms. These creatures are fixed in place, therefore they rely on the flow to bring the food to them. The food is then captured by mucus or stinging cells, or filtered through mouth and gills. In addition to sharing the same digestivity challenges as the fishes, they have a even bigger obstacle to overcome - the act of preying. Even if one were to turn off the wavemaker and target feed, majority of the fine food are not captured. The glowing yellow color of redsea ab+, or the powdery cloud of reefroid, these represent coral food which remains in the water column. Here is the conundrum. On one hand, we want to minimize decaying foodstuff in the water, on the other hand, those food stuff needs to be in the water for a long time for meaningful feeding to occur. To make matter worse, we can't just reduce the amount of food used. This will just cause less food to pass by the sessle lives, negatively impact their chance of feeding. Lesson from Reefs I'm not anywhere close to an expert on coral nutrition, but I would like to take a pointer from reef waters itself. The water provide food for the corals because there is a constant supply of numerous living plaktons. Wait! If the planktons are alive, they will not breakdown easily, and they will not impact the nutrient level in the water! So what kind of plankton should I introduce to the aquarium? I could start a culture of phytoplankton or even some copepod. However, this is tedious, and the culture medium is laiden with nutrients for the phytoplankton. Fortunately, I have other options. Two options really. Bacterioplankton from shaking the zeostone, as well as the diatoms which I encouraged to grow using Sponge Power. These planktonic lives recycles the dissolved nitrate and phosphate from the water. Effectively feed the corals. There is no real need to feed the coral on the daily basis. With less food wasted, more money is saved, and the pressure for water quality also reduces.

@peedeers I did a bit more reading up on the nutrition utilization by marine fishes. A few points can be discussed 1. Proteins from marine origin can be highly digestible 90+%, While terrestrial proteins are much worse 40-70+% 2. Digestibility of proteins is largely dependent on the quality of the source material 3. Digestibility of raw starch is low <50% while the cooked starch is higher >80% . With the higher prevalence of cold extrusion pellets, there maybe an impact on starch digestibility Here are two references http://www.fao.org/3/s5347e/S5347E14.htm https://fas.biomedcentral.com/articles/10.1186/s41240-016-0027-7 If anyone have a lab to conduct digestivity studies, that would be great.

I think you are right! Binders are mostly carbonhydrate, so they don't contribute to nitrate and phosphate in the water. However, I believe the presence of excessive available carbohydrates may have some impact on the bacteria population in the aquarium. In terms of the digestability of proteins and fats, that's another issue all together. Pellet quality is an area where more discuss should happen. Let's keep the discussion going! Fair point. When I write this I was thinking about the idea of feed conversion ratio. In a way this is more critical for reefes than fish farmers, because we need to deal with unconverted food. I think those are fine choices, just tedious. I used to feed my fishes with blended live clams before with good results. But like I said, tedious. It's also not easy to be consistent from batch to batch when it comes to chopping. Another thing is, I would only use live seafood to do this, they are less likely (I think) to have preservatives such as sodium tripolyphosphate. Thank you @VANAN and @Maipian80 for your encouragement!

Feeding the Aquarium The top of the line water processing facilities will do little to clean up the rivers if the factories and farms dumps chemicals indiscriminately. It's much cheaper for a country to control these polluters compared to trying to undo the damage. Same logic goes for reef aquarium. It is easier and cheaper to ensure less pollution enter the aquarium, than to try to extract the pollution from the water. That's why, I believe limiting the pollution is the first step towards health reef environment. However, it is crucial to note, that nutrient and pollution are not one and the same. One can feed the aquarium a lot, and cause very little pollution; while someone else may be heavily polluting the aquarium with minimum feeding. It all depends on how the feeding is done. Who Needs Food in the Aquarium? I would like to categorize the feeding clients into 3 categories: 1. Those who chases down the food, such as fishes and invertebrates 2. Those who wait for food to come to them, such as coral and sponges 3. Those who don't really "eat" such as bacteria and algae In an properly cycled and matures system. The population of three groups don't fluctuate much. Therefore the feeding need is always there. The Chaser Fishes and some invertebrate goes after the food and extract them from water column. Their feeding is efficient, since they don't need the whole water volume to be flooded with food. In fact when some pellets are added into the feeding tube, the pellets are often wiped out before they drift very far. Feeding for this group is, by nature, rather targeted. It's also easily to evaluate how much food is consumed. If the food is left unconsumed, it starts to decompose under the effect of bacteria action. This process consums oxygen, release carbon dioxid and lowers pH. It also release nitrogenous and phosphourus compounds. A source of pollution. What's unseen is even more crucial. If a fish consume the whole pellet in one swallow. Does it mean none of the nutrient is leaked to the water? Unfortunately, this is not the case. The food consumed by fishes and invertebrates must first be digested. Undigested food will just get excreted, before they start to decompose in water. Take a look at the following ingredient of a pellet. The second on the list, derivatives of vegetable origin, is the second most abundant ingredient in the list. These are likely wheat or soy flours used as a binder in the pellet forming process, but these are also terrestrial ingredients. The fishes may experience difficulty at digesting these. What happen to these components if fishes cannot digest them? They gets excreted as fish poop, and the bacteria in the tank acts on those poop, and break them down into nitrtates and phsophates. It's almost as if part of this pellet is not consumed at all. Therefore picking a good pellet is critical not only to ensure fishes recieve suitable nutrients, but also minimize the impact of pollution. My definition of good is that majority of the ingredients should be marine origin, with as little binder as possible. Currently I'm using NewLife Spectrum pellets and TDO Chroma Boost. Recently, I came across Fauna Marin pellets. Interestingly, there is no terrestrial orgin ingredients in the food. I expect this food to be highly digestable. As the result, I expect the impact on free nutrient in the reef is minimal. I doubled my feeding amount, with the addition being the Fauna Marin Pellets. Just like how I predicted, there is no visible impact on the phosphate and nitrate concentration.

Zeolight allows the coral to feed like this, 24/7 2051426001_Untitled-Sequence0151.mp4

Phosphate Management One of the challenge in my previous aquarium is that phosphate is never truely well managed. Phosphate media needs to be used on a fairly regular basis to keep the phosphate level reasonable. As I embark in the direction of internal recycling, getting those phosphates to become part of the cycle becomes essential. What kind of organism takes up phosphate? Cyano and dino are effective at removing organic phosphates, but they are a plague in the aquarium, and not many organism eats them. Brown hair algae removes inorganic phosphate well, but they are unsightly, and not preferred by tangs either. Macroalgae tends to use up a lot more nitrates than phosphates, thus not meeting my need. I need an organism which use a lot of phosphate to grow, not toxic to aquatic life or smother them. Finally, they need to be a source of food for tank inhabitants. Is this too much to ask? Turns out there is an organism which fits perfectly. Diatoms are Friends, and Food Consider diatom, harmless, nutrient rich phytoplankton. Visible diatom can look like brown dust on the aquarium substrate, at the same time, a population of diatom floats freely in the water column. The growth and reproduction of diatoms removes dissolved phosphates from water. At the same time, these nanoplanktons are readily captured by corals as food. Win-win situation. In order to induce diatom growth in the aquarium, Sponge Power is used daily. I have used sponge power before, it encourages formation of growth tips in many acropora corals. It also have the pleasent side effect of inducing some diatom growth. Perfect fit for my aquarium. If too much is used, a thicker layer of diatom will cover the sand, therefore the dosage is adjusted so that there is a slightest hint of brown on the exposed sandbed at the end of the day light duration. The little bit of diatom in the sandbed is cleaned up my nocturnal clean up crews, and the sand bed is clean as new the next morning. Zero Phosphate?! The phosphate level has remain at 0ppm (Hanna ULR) for the past 2 month. However, livestock shown no adverse reactions, instead, the polyps extension has been quite pronounced. I believe the reasons are three fold: 1. The corals, with their mucus and bacteria holobiont, has the ability to concentrate dissolved nutrient from surrounding waters. 2. The constant supply of bacterio- and phyto-planktons provide the coral another quality source of energy. 3. Lastly, Hanna ULR has its limitations, the limit of detection is 0.015 ppm, and the organic phosphates are not detected by the test kit. Therefore a zero on Hanna doesn't mean there is no phosphate in the water. Thus I will happily let the phosphate be.

Zeolite In My Acropolis So, the Acropolis is powered by zeolite. Majority of the products comes from Fauna Marin Zeolight system. However, I do make use of several KZ Zeovit system products to meet the need of my aquarium. Let me share with you how the modified zeolight system is run in my tank. On the Surface It is possible to run FM Zeolight system with almost full automation. For the lack of dosing pump, and my inclusion of KZ products, the aquarium is maintained daily. Dosing: 5 drops of Coral Vitality (FM) by hand daily 5 drops of Sponge Power (KZ) by hand daily 45 ml of All-for-reef (TM) on a single motor doser, daily. Top up water, if needed. Feeding: Fish: hand feed a mixture of selected pellets 3-5 times a day Coral: frozen mixture of Min S, Amin, and Organic. Once every 2-3 days. Maintanence: Change floss every 4-5 days Change Carbon every month Partial replacement of zeolight every month. Dose Color elements as and when I feel like it . It's fairly straight forward, less than 5 minutes a day. In terms of costs. The main costs comes from the zeolight stones and activated carbon. The dosing products, although expensive, can last for a long time. (I had used sponge power before on a Berlin system aquarium. The dosage needed is much higher). Considering that I don't need to rely on expensive GFO to keep the phosphate in check. I think it's not too bad a deal. Under the Hood The nutrient management is powered by three pieces of critical hardwares. 1. AquaExcel EC80 skimmer. When it comes to skimmer, a simple workhorse is all I need. Start with a massive reaction chamber, and slap on a decent needle wheel pump. One does not really need anything else when it comes to effective skimming. This skimmer helps to remove some bacteria flocks. It also helps to increase the dissolved oxygen level during lights off (interestingly, during light hours, the skimmer decreases the oxygenation) 2. Skimz Automatic Zeo Reactor. This is the hardware that make me feel that zeolite based system can be practical. The reactor makes use of an oversized DC pump. During normal operations, the flow is slow. However, every hour, the pump is set to pulse mode with maximum power. This fluidise the entire zeolite completely for 30 seconds. The flow and the collision between media particles effectively knocks out surface bacteria films. Compared to a reactor which stirs the media once a day, or a manual reactor, this approach spread out the release of the bacterioplankton (mulm in Zeovit terms), ensure the corals always have food to capture from the water column. A device to help with nutrient export, and feed the corals 24/7. How much better can it get?! 3. ORP meter: compared to a Berlin style reef, zeolite based system consist of a much smaller organism size. Remember about not feeding the chaeto? The goal is also to not feed and encourage organisms to compete for nutrient wij the corals. As a result of the smaller biodiversity, zeo light based system is less adapt at dealing with nutrient spikes. Without an over-sized food web to wipe out organic nutrients rapidly, zeolite based system are slightly more prone to cyano/dino outbreaks if the organic is not well managed. Other than studying the algal growth and infer the state of organic nutrients in the aquarium, an ORP meter can also be used to provide an indication. When the ORP is low, it will be ill advised to add in various coral food and liquid formulae. On the other hand, if the ORP is too high, it signals the need (or opportunity) to step up on coral feeding.

From Nutrient Export to Nutrient Management As my replacement tank is getting ready, I started planning the filtration system of the aquarium. I was a subscriber of high inport, high export strategy, firmly believe in providing as much food as possible to the aquarium, while removing as much nutrient from water as possible through different techniques. I had some measure of success using Nitraguard Biocubes. They are a form of solid carbon, and are effective in removing nitrates through bacteria growth and skimming. However, they are less effective at removing phosphates. Thus I use FM Ultraphos, aluminium oxide based phosphate media is much cheaper and easier to implement. In my experience, a filtration system fully driven by carbon dosing are fairly prone to imbalance. Thus I decided to include chaetomorpha to shoulder half of the export duty. I do not like to have light spill in my sump, thus I opt for an AquaExcel Macroalgae Reactor. Effective is an understatement. The nitrate and phosphate are stablised at almost undetectable level very quickly. On one hand, lots of pellets and coral food are added into the aquarium on a daily basis; on the other hand, the skimmer pulls out copious, dark skimmate. The small handful of chaeto quadriple in size after one month. As I pull out the lumps of chaeto to throw away, an idea clicked. What am I really growing? Chaeto and skimmates or coral and fishes ? In another word, if most of the fish and coral food (expensive) end up becoming chaeto and skimmates, is it a sensible proposition? Is there a better way? Enter the Zeolite If improving the efficiency of nutrient management is the goal, Zeolites are a god send. These stones selectively absorbs some nitrogenous compounds, stripping them from the water column and prevents formation of nitrates. But they are much more than a nitrogen sponge. The rocks also provide numerous surface for bacteria to grow. That's not all, through the regular rinsing of the zeolites, the bacteria flocks are dislodged to be skimmed out, or even better, to feed the corals. Now how is this different from biopellet reactors? Don't they also make use of bacteria plankton to export nutrients? There is a huge difference! Carbon dosing export nitrate and phosphate by adding carbon source, while the zeolite system recycles the dissolved C, N and P and fix them into living biomass, effectively reduce the free nutrient in the water. In a normal aquarium, if 10% of food is used by livestock, 90% is exported as waste. In a zeolite system, that 90% is recycled, fed back to the display tank repeatedly. It's not hard to imagine how this can massively increase the utility of the food fed. In essence, ULNS is a by product. The gem of a zeolite bases system is the efficiency of feeding, as well as the continoued presence of food for corals.

Nutrient Management My understanding of reef nutrient management has evolved significantly since the beginning of my reefing journey. My old (leaked and replaced, RIP) aquarium allow me to experiment with various bioload levels and nutrient export techniques. It's in the recent months when I have replaced and setup this aquarium, I had the moment of eureka, and had new perspective on nutrient management. Allow me to share this evolution with you. 1. A Cautious Beginning When I first cycled the old aquarium, I was very cautious. I used 16 blocks of marinepure brick (massively overkill), and keep a modest number of fishes. The protein skimmer, which I'm still using now, is rated for 4000L. Plenty sufficient for my 1000L aquarium. I was cautious in feeding my fishes, fairly disciplined to control what goes into the aquarium. I did these based on what I read on various forums about maintaining good water parameters. The idea sounds very simple, very logical, and very sustainable. Afterall, by polluting water less, water will be cleaner, right? To give myself a peace of mind, I started measuring nitrate and phosphate in the aquarium. It was okay for a fish only tank, not great. A nitrate level of 25ppm and a phosphate level of 0.2ppm is not that bad, but certainly could do better. I started trying to reduce feeding, and try to add in more filter media as well as more bacteria. Surely it will help? Alas it's not so. Cutting down feeding, adding bacteria barely manages to reduce the nutrients in the tank. Well... Since cutting down feeding doesn't do a thing, why shouldn't I feed more? At least my fishes will be happier. 2. Reckless Abandon Things swing the other way quickly. I started to increase the. Bioload, adding more and more fishes. I started to feed the fishes more, pellets, frozen, and nori. Before long, I was adding fish food by spoons into the aquarium multiple times a day. Through it all, the nitrate and phosphate level remains about the same. I have to replace floss more frequently, and clean my skimmer more often. Other than that, everything goes well, fishes were fat and happy. Then I thought, perhaps, it's cool to add some coral into the tank. What a costly thought! In order to try to keep corals, I thought I need to bring the nutrient level down. So try I did. I started with carbon dosing. NOPOx. Within weeks I start to see the impact. The skimmer produce ridiculous amount of scum; nitrate started to dive, phosphate also started to decrease slowly. I thought, hey, this is great. All the problem in reefing solved! Little did I know what follows were cyano, dino, endless use of gfo, carbon, purigen and a hundred other products. I begin to realise reefing is not as easy as reducing a nutrient. There is a delicate balance, a thin line to walk upon. The complication from carbon dosing lead me to seek out other export measures. Algae refugium and ATS. Both of them helps tremendously with nutrient export. I was pulling out cupful of turf algae every week, at the same time, cleaning loads of skimmate every few days. Looking at the amount of waste thrown away, I was satisfied. I also learnt to dose nitrate to help with phosphate reduction, slowly able to balance the CNP ratio in the aquarium. This is the period of time where I hold redfield ratio as the golden truth. This is also when I fully embrace the idea of high input, high export philosophy. Fishes are growing, corals are doing ok. Water parameters are good and stable. Without water change, the level of nitrate is less than 1ppm, and phosphate was around 0.03 ppm. Isn't that great. But as I add scoop after scoop of fish and coral food, pulls out cup after cups of turf algae. There is a nagging feeling of something is not ideal. I couldn't put my finger on it then, but my assumption of nutrient export will be challenged soon, at a fundamental level. Then my old tank leaked, a replacement tank is ordered. The next stage of journey begins.

Thank you very much! I will try to write down my experience with different equipment and design choices. Hopefully can lead to some discussion.