tuan

Fantastic ! Many congratulations... life will never be the same again, all for the right reasons!

Thanks guys. So nice to see others can appreciate my efforts. Such kind comments certainly cheered me up despite the nutters in London.

You don't have to, but it sure looks nice though

Ha haa... actually they are multiplying. Had one, became two.. four.. eight. So I'm actually praying for them to move so I can remove and sell/trade them. Got rid of four already !

Rose bubble tip anemones ( four of them! ) taking over a large section of the tank.

Ha haa.. though I'd throw in a 'brand wagon' to see who bites! Mylar is just reflective plastic sheet, the stuff they use in hydroponic (aka drug boys) to reflect light. It's plastic and 95% reflective. You can use it to line your hood for example. Here's more: http://www.growell.co.uk/p/0309/Mylar_Refl...e_Sheeting.html I use some to line the bottom, back and sides of my frag grow out tank to reflect the light back in. It's only effective if you keep the glass clean though

Actually, there are a huge number of reefers on RC that just have to be on the "right band wagon" whatever that is. They jump on in droves and follow a leader without question or understanding. They jump off in droves on to the next fad... Two /three years ago it was the DSB club, you know "I have a DSB and I'm proud of it.. neh neh nah nah". Search teams spread across the states hunting for that elusive Sanddown sand... Ebay bidding going through the roof for a bag of sand! Just dump them it lads.. 6inches ought to do it, simple! Then now, "I've been BB for months now and I'm wearing the badge proudly"... yet another band wagon. Have a search for 'Starboard' and see what I mean.. everybody has got to have a 'Starboard' now if you want to be in the club. There are crazy guys trying to ship 8 feet worth of a piece of plastic around the world! May be I'll start another fad and see... say, Mylar reef! My frag tank sits on a piece of Mylar foil to reflect the light back up, wow, look! Double the brightness with T5

Not sure how it came about but I'm certainly not against DSB (or any methods in fact). I think you've misread my posts somewhere, but I can't be against DSB when I'm keeping a very large DSB myself, much larger than the majority of reefers out there. Believe me, adding 8" worth of sand to cover 46 square feet is a serious commitment! My system is far from being polarized into specific camps of must have this and must have that. I make use of all the methods and try to keep them in balance. I have strong skimming, deep sand beds, strong flow, algae for nutrient export.. everything! To expand on the sand clumping:- First example:- If you take a bucket of sand and keep on adding to it a very fine dust like particles, eventually the gaps between the grains on the surface becomes compacted and blocked with the fines. So if you have an in-tank DSB, not enough flow, not enough infauna, then the detritus will do exactly the same to the sand and make the first inch or so layer become so compacted that water cannot flow to the lower layer. Second example:- Take a bucket of sand (especially aragonite based sand) and tank water. Drip into lime water (Kalk). What happens is the calcium ions will crystalize on the surface of the grains of sand, and eventually, turn the top surface solid. This is what happens when the DSB in the tank do not have the fauna to gently stir the surface and break up the bonding between the sand grains. Especially when lime water is added incorrectly or the Alk level is pushed and kept very high (many reefers keep Alk at way above NSW in the race to get growth). Thirdly: The action of the bateria coating and fauna on the sand itself can dissolve some of the surface (e.g. waste can be acidic), and then re-crystalize. So overtime, if not disturbed, can cause the grains to bond. So there are many factors which make the top of the DSB becoming a barrier preventing water diffusion, and so stop the DSB from functioning.

Nicely done AT. Though I can't see any structure for all the corals in there.... you need a bigger tank!

ian, I'm confused now. Is the whole post above aimed at my comments? Yes, it is the bacteria that performs the filtration, and not the infauna. But, without the infauna, the surface of sand bed quickly becomes a solid plate like concrete. This is due to blockage from detritus, due to precipitation of calcium crystals, due to some dissolution and then bonding from the action of the biofilm coating the sand particles. When the sand solidifies like this, it obviously stop functioning as a filter as water can no longer diffuse downwards, and so the bacteria population below the surface are starved and die off. Which is why the infauna (& diversity of) is so important. Sure in experimental tanks you can just use bioactive sand and watch ammonia disappear and observe the full denitrification process. In a real reef tank this is not true. I also commented on the avoidance of sand shifters fish/star fish and even hermit crabs as these will all feed on the infauna that we're trying to protect. Worms in the sand is critical as part of the process of keeping the sand lose. Their movements actually doesn't disturb the sand layers that much, if you're sad enough to sit and watch how they move through the sand layers. Well - I read and read for years, even after many people have reported problems with DSBs, and then I installed my tanks with 46 square feet worth of deep sand bed in them... don't think I'm deriding them in anyway here

Oops - another misleading word/misconception. When I say "Live sand", I mean sand that is populated with critters/pods/worms ie.. the fauna, and not just bacteria. Now some manufacturer/reseller are also selling "live sand" in a wet bag which isnt the same thing. They're talking about bacterialy active sand, but not much else really, what else can live in a sealed bag with a shelf life of nine months? To make your own bacterially active live sand, get some sand, put in bucket with sea water/salt water, add in a piece or two of live rock rubble or a cup of sand from existing system, or anything that came from a living reef system... add some food (piece of shrimp/fish etc..) and wait a few days. You'll probably get more 'life' in your bucket than a shelf full of those bags IMHO.

Just rolling back a little here. BBT is nothing new. It's the basic Berlin technique and has been around for umpteen years. Everybody keep going on and on about BB as if its a new invention or something... The point is, it was around before people (mainly the US guys who started) adding sand, and then deep sand beds. So the question of how long has BB tanks been running can already be regarded in 15-20 years. It does lead to the question though.. if Berlin systems have been sucessful in the past (and still is), why did DSB come about at all? Another point is live sand is critical to a DSB. The whole point is that you have a myriad of organisms living in the sand to slowly churn it and prevent the surface become compacted solid or clogged up with detritus. Food (including fish waste) that lands on the sand are dealt with instead of rotting. This food is basically consumed by some organisms, the waste product is consumed again and again by more and more organisms be it worms, pods, bacterial level. Obviously the food cannot ultimately become nothing, but whats left, is basically inert. Mother nature take care of this whole process because if there's something that's edible/useful to some creature it will be consumed. But now, we have the left over of very fine dust like particle of detritus, and obviously you cannot go on adding this stuff into the sand bed forever. What you can do though is periodically blast sections of the DSB with a jet of water, disturbing the top layers only, and bring back into the water column this remaining detritus. Mechanical filtration/skimming will then remove it from the water column and help to extend the life of the sand bed. Occasional strong water flow that shift the sand surface about a little also help to simulate this 'storm process', just like in nature.

Don't know about "those who have tried it"... it is working for me. I do have macro algae refugium, skimming, PO4 export via gFe compounds.. everything going. I counter-act the "problems" of the DSB by putting mine in a 8' x 2' feet refugium, totally separate from the main tank, without any fish predators at all. Half of this tank is kept in the dark (ala cryptic zone), there are a few pieces of live rock (introduced fresh/uncured). The bubbles can be seen in both dark and lit zones and there is no way it can be Oxygen (there's no explaination of why O2 would be generated). The water column in this tank is buzzing with free swimming pods. All kinds of feather dusters/sponges/filter feeders are thriving. The whole tank is packed full of worms/asterina starfish/small white brittle stars.. and unfortunately loads of aiptasia too (as there are no predators on them). I feed this tank periodically with a mix of food, almost as much as I feed my main display tank. The lit side is bathed with 2x 150w MH during the night, bristle worms spawn quite regularly as well as a myriad of chitons/stomatella etc.. I guess what I'm saying is that yes a DSB can be hard work, but it does work, although I would like to give the tank another 5 years to really test it. What you cannot do though is to rubbish it off just like that as it may well be a viable option for larger systems.

But it does. That's the point of the deep sand.. the deep layer of sand has anaerobic bacteria which consumes nitrates and produce Nitrogen as bubbles. Exactly like the pores in live rocks. In fact.. just like the bottom of a plenum system. The long term problem is when the sand has become a solid clump which inhibits the diffusion of water down to the lower layer and so the anaerobic bacteria have no food and die off. You have exactly the same problem with live rocks in a poor environments. After a while the detritus build up, the algae growth etc.. block up the pores in the rocks and you will also get zilch for denitrification. The analogy is to wrap your live rocks in food wrap/cling film.

Followed this thread for a while and thought I try out my comments here as there seem to be less flame throwers about! With all this 'fashionable buzz words' around, DSB/BB/Starboard blah blah.. it's easy to forget the basic principle of a reef tank filtered by live rock. The so called fashionable 'BB' is nothing new. The principle of a tank with living rock and skimming was started many years ago called the "Berlin method". The point is porous living rock has the capacity to fulfill the complete biological filtration cycle including denitrification. Many of us had successful tanks then for many years with just live rock filtration, good circulation and skimming. DSB was an 'invention' later which basically 'discovered' the fact that a few inches of sand can *also* provide denitrification, effectly reduce the amount of live rock you needed to have with the advantages of:- reduce cost, better for environment and more space in the tank. Aggressive skimming is not exclusive to any method. It's principle is simply remove as much waste (both particulate and dissolved organics) as possible before the waste has a chance to be broken down into the water column (and therefore the biological filter has less work to do). Another myth about flow and DSB... it is possible to have high flow rates and sand. In the reef the flow rate is many times what we can ever dream of achieving in our glass boxes, but is the water column completely solid with all the sand that's around, nope. It's all about placements of the pumps and chosing the types of pumps. If you have narrow jets blasting down or hitting the glass so hard that they deflect down into the sand then yes you will get sand blowing around. In my tank I have 60x tank volume flow rate, and a large DSB, admittedly the large area and depth make it easier but there is still a lot of flow and the sand doesnt move about that much. There are sand dunes etc.. and some does move at the start or if I change the flow somehow, but after a while it all settles down. So why is there so many tank failures from DSBs? The answer lies with the reef keeper! Many people simply read about DSB on the web and without understanding the principle of it and thought:- wow, this is easy right, you just throw in a few inches of sand and that's it! Skimming is neglected. Waste exports (PO4) weak.. predators added (sand shifting star fish/ blue cheek gobies) all aim towards 'keeping my sand pristine'. Well... it's no surprise then that the tank crashed. Oh yeah.. the sand is leaching PO4 this and that comment. Well.. sure, if the sand (and the rest of the tank) has been immersed in sky-high PO4 all this time then yeah, it'll leach some back. Now had the PO4 been non-existance all this time then how can it be leached back from the sand? It can't. Another popular one is the black sand of death. Well.. if you go and disturb the sand bed and turn it upside down then sure enough you'll have problems. Say what would happen if you go and split all your live rocks into pieces within the tank? Yes yes.. the inside of your beautiful living rock is also black and stink of rotten eggs too, it's meant to be, in the anoxic environment that's what you get. So there... that's my two cents worth anyway