Reefing equipment

[Harlequinmania]

I am pining up these information with regards to different types of reefing equipments available in the market and what it does to our aquarium system ,and i hope these information help as a easy references guide for newbie and members .

** Some of the information is extracted from different sources and compile together here for easy reading and understanding. **

HAPPY REEFING ...

Calcium Reactor

Calcium reactor or some called it Calcium carbonate reactors have become a popular way of replacing the calcium and carbonate taken up by corals in the process of calcification.

In a layman terms, it is a device used to create blance of alkalinity in the system by which a container filled with calcium carbonate (CaCO3) media over which aquarium water is passed with the addition of carbon dioxide. Adding carbon dioxide lowers the pH of the water, making it acidic, and dissolving the calcium carbonate to provide the aquarium with calcium and alkalinity.

A calcium reactor is one of the most efficient ways of constant supply of calcium into your aquarium.

Kalkwasser Reactor

Kalkwasser reactor or something called Nilsen reactor is a simple and reliable way to add kalkwasser to your aquarium . It uses a chamber in which a motor or a magnetic stirrer keeps the kalkwasser agitated. Some other design uses a small pump to keep the water circulating in the reactor and the solution saturated. Kalkwasser is an excellent source of calcium, hydroxide ions to buffer alkalinity (PH), an unmatched ability to encourage coralline algae growth, and it precipitates phosphates out of your system water.

Protein Skimmer

A protein skimmer or foam fractionator is a device used mostly in saltwater aquaria to remove organic compounds from the aquarium water before they break down into nitrogenous waste. Protein skimming is the only form of aquarium filtration that physically removes organic compounds before they begin to decompose, lightening the load on the biological filter and improving the water's redox potential. Although the process of foam fractionation is commonly known for removal of waste from aquaria, it is, in fact, a rapidly developing chemical process used in the large-scale removal of contaminants from wastewater streams and the enrichment of solutions of biomolecules.

The basic units design of a skimmer consists of a main chamber through which aquarium water flows. Air is injected into the column as fine bubbles. The surface of the bubbles collect proteins and other substances and carries them to the top of the device where a collection cup allows the foam to leave the main chamber. Here the foam condenses to a liquid, which is removed from the system. This material can range in color from a light tea to black tar.

Every skimmer operates either by co-current flow, in which the water flows upward in the column along with the bubbles, or by counter-current flow, in which the water flows downward against the direction of the bubbles. Counter-current skimmers are more efficient because of the greater contact time the water has with the bubbles. And they are basically two main types of Skimmer ; Air pump or motor driven skimmer.

Air stone driven

The original method of protein skimming, it is not completely obsolete, although many newer technologies have eclipsed this method. The air stone is a ceramic block with an air hose attached that runs to a small air pump. The stone is placed at the bottom of a tall column of water. The tank water is pumped into the column, allowed to pass by the rising bubbles, and back into the tank. To get enough contact time with the bubble, these units can be many feet in height. While this method has been around for many years, many regard it as inefficient for larger systems or systems with large bio-loads.

Aspirated or Needle wheels skimmer

The premise behind these units is that a venturi valve can be used to introduce the bubbles into the water stream. The tank water is pumped through the venturi, in which fine bubbles are introduced, then enters the skimmer body. This method is popular due to its compact size and high efficiency.

A new variation on the venturi is the needle wheelâ„¢. This method of bubble generation evolves from another method that uses a turbine within the water stream to create bubbles. Essentially this method uses a pump to pull water past a venturi - before the pump - then past the pump's impeller which smashes the bubbles into very fine bubbles, and into the skimmer column.

Downdraft Design

Pumped tank water enters through a small vertical column next to the main column, that contains a plastic media that shreds the water, entrapping air in to the stream. The result is a milky white appearance of very fine bubbles. The stream enters a mixing box and is allowed to rise within the reaction chamber. This is one of the current top skimming methods due to its compact size and high efficiency.

Predominantely known as a "Beckett" protein skimmer, which is based on a brand name of a foam jet, or pond foaming nozzle producing very fine bubbles.

Spray Induction / High Speed Aeration Skimmer

This method is related to the downdraft, but uses a pump to power a spray nozzle, fixed a few inches above the water level. The spray action entraps and shreds the air in the base of the unit, which then rises to the collection chamber.

Venturi Operated

The premise behind these units is that a venturi valve can be used to introduce the bubbles into the water stream. The tank water is pumped through the venturi, in which fine bubbles are introduced, then enters the skimmer body. This method is popular due to its compact size and high efficiency.

A new variation on the venturi is the needle wheelâ„¢. This method of bubble generation evolves from another method that uses a turbine within the water stream to create bubbles. Essentially this method uses a pump to pull water past a venturi - before the pump - then past the pump's impeller which smashes the bubbles into very fine bubbles, and into the skimmer column.

Different types of skimmer arrangement in marine system

Ozonizer

An ozonizer is a type of air or water purifier which uses ozone 03 to kill bacteria and filter out a wide range of contaminants. Ozone itself is a form of oxygen, though much less stable than the common O2. Ozone is present naturally, mostly in the upper levels of the atmosphere, where it helps deflect ultraviolet radiation. Concentrations of ozone below the atmosphere can be a serious health risk, as ozone is highly toxic to humans and most other forms of life.

Ozone has been used in reef aquaria for many years. It is claimed to have many benefits, ranging from increased water clarity to decreased algae , increasing ORP, reduce nitrate, increase skimmer performance, decrease yellow water ect. However it should be use and handle with care as too much 03 in the water will affect the live stocks and potential undesirable health effects on human if too much is breath in. A reliable ORP controller can be used to control the amount of 03 content in the water as well as using carbon at the water outlet path to reduce excess 03 in the water.

Nitrate Reactor / Denitrator

There are basically two main types of denitrators, one using anoxic conditions to convert nitrates to nitrogen and the other uses sulphur to remove nitrates and phosphates, and the possibilty of adding calcium into the system as well.

Basically, a sulphur Denitrator uses a tubular acrylic column in which is filled with sulphur beads. Seawater is pumped through the sulphur at a very slow rate " this is a very fast drip when the device is mature.

The action, by bacteria, takes place in a very low oxygen environment. As the bacteria do not have a ready oxygen supply, they are forced to use the nitrate, from which oxygen is extracted, breaking down the nitrate. Generally one molecule of nitrate is replaced by one molecule of sulphur. The sulphur has no detrimental affect on the seawater as it is present in a high percentage anyway. The only result to watch is that the output from the sulphur can be acidic. This is easily remedied by running it through some calcareous material before it returns to the aquarium. The water flowrate through the reactor is similar to that of a calcium reactor. A by-product is the production of carbon dioxide, which may lower the alkalinity and pH in the system. The production of carbon dioxide is minor so will have minimal effect on the system as a whole. Calcium carbonate can also be added to the sulphur denitrator, taking advantage of the depressed pH to dissolve the calcium carbonate and introduce calcium and alkalinity to the water at the same time.

Sulphur denitrators are efficient and easy to run. .

Fluidized Bed Reactor

A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid is passed through a granular solid material (usually a catalyst possibly shaped as tiny spheres) at high enough velocities to suspend the solid and cause it to behave as though it were a fluid. This process, known as fluidization, imparts many important advantages to the FBR as it help in maximium efficiency absorbation of the media in the chamber .

[Harlequinmania]

More inforrmation on using Ozone

**Extracted from Reefkeeping.com**

Ozone is often used by reef aquarists to "purify" the water. To most aquarists that means making the water clearer, and it certainly does that in many cases. How to optimally accomplish that task without risking the aquarium inhabitants' or the aquarist's health, however, is not always obvious.

The figures below shows a sample of a schematic ways of how ozone is typically used in a reef aquarium. Some of these steps may be eliminated in particular applications, but aquarists should understand that by doing so they may be using other than optimal procedures.

The process starts with an air source, usually a normal aquarium air pump. The air is often passed through a dryer where a hygroscopic material such as silica is employed that removes much of the water from the air; this is referred to as an air dryer. After passing out of the dryer tube and through an air check valve to prevent water from backing up into the system, the air enters the ozone generator itself. Drying the air in advance enhances the ozone generator's effectiveness.

After the ozone-laden air passes out of the ozone generator, it is sent to a mixing chamber where aquarium water and the gas are mixed well and are kept in contact for at least a few seconds. Aquarists often use skimmers or specially made ozone reactors for this purpose. Selection of suitable materials for these devices is a concern as the ozone can degrade some types of plastic, rubber and tubing.

Inside the contact chamber, the ozone reacts with many different chemicals in the seawater. Most of the benefits that accrue from ozone's use must take place in this chamber. Inside it, for example, the water is made "clearer" as certain light-absorbing pigments in dissolved and particulate organic molecules are destroyed, generally by oxidation.

Not all of the products of ozone's reaction with aquarium water are beneficial, however. Water leaving the contact chamber is optimally passed over activated carbon sufficient to remove the remaining ozone produced oxidants. The carbon breaks down most of these potentially hazardous oxidants before they enter the aquarium. The air passing out of the reactor also contains ozone and is also best passed over activated carbon to reduce the concern for airborne ozone's toxicity.

In order to ensure that not too much ozone or its byproducts enters the aquarium, aquarists monitor the aquarium water's ORP For those aquarists using a small amount of ozone, monitoring may be adequate. For those aquarists using large amounts of ozone, an ORP controller may be important. It can be used to shut off the ozone if the ORP rises above a set point (that point being either an emergency shut-off point that is rarely, if ever achieved, or a target ORP where the generator is actually running only part of the time and only when the ORP controller says that ORP needs to be raised to the set point).

Most ozone applications used by reef aquarists employ an air pump as their initial air source. While some units (such as one by Enaly) combine an air pump with an ozone generator, that is not the normal setup. Pressurized air in a cylinder or pumped tank, or even pure oxygen, can also be used, but due to their added expense those methods are unlikely to be used by most hobbyists. The only situation where aquarists might not use an air pump would be if the air/ozone mixture were being sucked through the ozone generator into a venturi, a common device on many skimmers, that allowed it to then enter a reaction chamber of some sort. In general, this is not the most common application, though, as an air dryer may put too much back pressure to allow a venturi to adequately draw in enough air.

Air drying

O zone generators using corona discharge operate most efficiently when the air entering them is dry. Many aquarists know the rule of thumb that ozone generation efficiency drops by about a factor of two between dried and undried air, and some Ozone maker claims that drying the ambient air with a relative humidity of 50% to dry air with a dewpoint of -40°C causes a 50% reduction in the ozone output . The simplest dryer is a plastic tube filled with a material (Silica Gel) that binds to moisture in the air. The air flows in one end and out the other, and gets dried while passing through.

Gauging how much ozone is necessary is not trivial, and may depend strongly on the desired outcome from dosing ozone, how it is used and the other husbandry practices used in the aquarium. Clearing up yellowing in the water, for example, uses far less ozone than is necessary to sterilize the water. Likewise, a good ozone/water reaction chamber might allow far less ozone to be used than is required by an inefficient use in a skimmer. That being said, most guidelines suggest on the order of 0.3 to 0.5 mg O₃/hr/gallon of aquarium water.

Ozone used on Skimmer

The ozone reaction chamber is the heart of the system. It is the place where air, laden with ozone, and water from the aquarium are mixed together. In the first article in this series I detailed the chemistry and biochemistry that occur in the reaction chamber. I also discussed issues relating to contact time and ozone concentrations with respect to some of ozone's potential effects (such as disinfection).

A variety of different systems can be used as contact chambers, and most reef aquarists choose to use skimmers. They use either their main skimmer or a smaller, inexpensive one that can run at a lower flow rate and potentially be sacrificed if the ozone degrades the plastic to the point where it no longer is reliable. Despite their widespread use with ozone, skimmers are not usually an optimal way to employ ozone for several reasons:

1. Their water and air flow rates, and even their engineering design itself, are optimized for skimming, not for ozone injection and reaction. The longer the ozonated water has to react, the more oxidation of organic molecules can take place. This is not a design criterion with skimmers, where the air/water contact time is maximized, but the water alone is not held for any purpose. If the water's flow rate is too high, and hence its turnover rate too high, the concentration of ozone in the water, and the contact time for it to react with organic materials, may be less than optimal.

2. Both the air and water exiting the skimmer should optimally be passed over activated carbon to reduce the highly oxidizing and toxic species being sent into the aquarium and into the aquarists' home air. Many skimmers are not set up to efficiently pass the air over carbon, and high water flow rates can make it difficult to achieve adequate contact with activated carbon.

3. Many skimmers are not designed using materials suitable for prolonged ozone exposure.

Nevertheless, the majority of reef aquarists who use ozone do so with a skimmer. Whether it is optimal or not, they have decided it meets their needs. How ozone is used with a skimmer depends critically on the nature of the skimmer, and too many different designs exist to provide many useful details. However, some suggestions for using ozone this way are:

1. Select a skimmer that allows a substantial volume of water to be contained within it, so that the ozonated water is not immediately swept away and passed over the GAC (where the ozonation reactions largely end).

2. Select one that lets you collect the air and pass it over GAC. A Sea Clone, for example, would be a poor choice in this regard as the air and water exit it from a fairly large opening. The ETS skimmer that I use is also a poor choice, as the air comes out of a tube that is also the skimmate outlet. It can, however, be used with a special skimmate collector (described below).

Ozone and the human health

Ozone in the air can be a significant health hazard to humans. Some studies had suggested that a level of 0.2 ppm was not a significant health risk. It is beyond the scope of this article to detail ozone's various health effects, but it should be apparent that if ozone can be used to oxidize and break down organic materials, then ozone exposure to humans, which are made up of organic tissue, is undesirable.

Ozone is a powerful oxidizer, and aquarists need to ensure that they are not adding too much to their aquaria. Besides properly sizing the necessary components (ozone generator, GAC treatment, etc.), there is one relatively simple way to ensure that the tank is not being overdosed, and that is by monitoring ORP (the oxidation reduction potential), as In dosing ozone to a reef aquarium, the more ozone that is added to the system, the higher the ORP will rise.

These contorller are very useful in that they can shut off the power to an ozone generator (and to any other desired devices) if the ORP rises too high. All an aquarist needs to do is tell the device what the upper ORP limit should be, and it is ready to go. Some companies sell ozone generators that incorporate an ORP meter or controller. These may be convenient or less expensive, but they do not incorporate any sort of inherent advantage.

The use of ozone in reef aquaria has advantages and disadvantages. Among the advantages is the improved clarity of the water. Unfortunately, a significant concern is the toxicity of ozone and its byproducts to both humans and reef aquarium inhabitants. The proper use of suitable equipment, however, can mitigate this risk to a substantial degree. For those choosing to use ozone, my recommendations are:

1. Size an air pump appropriate to the ozone generator and the contact chamber being used. An air pump with a variable flow rate can be useful. Use an air pump that can handle back pressure if the contact chamber will be pressurized.

2. Potentially use an air dryer to increase the ozone output, decrease the nitric acid output and prolong the generator's lifetime. If using a UV bulb ozone generator, an air dryer is not necessary.

3. Use a generator sized appropriately for your system, on the order of 0.3 to 0.5 mg O

3

/hour per gallon of aquarium water. While an inordinately large generator may not cost much more, it can risk overdosing the aquarium. As with many reef additives, using more than recommended is rarely better.

4. Many types of commercial or DIY air/water contact chambers can be used. Optimal systems will have a significant contact time between the ozonated air and the aquarium's water, will allow the ozonated water to react for a substantial period, and may be under significant pressure. Skimmers can be used, but are far from optimal.

5. For the safety of people in the vicinity of the aquarium, be sure to pass the effluent air over an adequate amount of activated carbon to preclude any ozone smell. A test kit or meter for airborne ozone detection may help ease aquarists' concerns.

6. For the aquarium inhabitants' safety, pass the ozonated water over activated carbon to reduce the concentration of toxic ozone and ozone byproducts in the water.

7. Monitor the ORP when using ozone. If it rises above 375 mV, and it may well not, be sure to carefully control it so that it does not rise undesirably high (above 450 mV).

8. Once the system is in full operation, the air flow, water flow, ozone generator setting, GAC treatment and other parameters should be adjusted to maximize its performance. ORP can be used to gauge the addition of ozone. A chlorine test kit can be used to gauge the removal of ozone and ozone byproducts from the treated water.

[Harlequinmania]

All About UV Sterilization

Ultraviolet radiation, referred to as UV or UVC radiation for sterilization purposes is a form of ionizing and non-ionizing radiation. UVA and UVB that are can reach the Earth’s surface are primarily non-ionizing and do not have enough energy to ionize atoms. However, the longer wave UVA and UVB can cause molecules to vibrate and rotate resulting in heating up.

The shorter wave UVC (used in UV Sterilization) light will ionize many atoms and molecules as compared to the even shorter wave Gamma Rays which will ionize most atoms.

Ultra violet sterilization is one of the most effective means of disease prevention in aquariums and ponds and for general water quality control in aquariums/ponds, as well the use of UVC Sterilization is useful in home, office, hospital air purification (& even UVC/Redox Blood therapy).

For this reason a properly installed/designed UV sterilizer helps improves a fish’ chances in fighting bacterial diseases or even parasitic diseases such as Ich that UV Sterilization is less effective directly in destroying.

Part of the reason for UV Sterilization (which is often missed) is that the UVC radiation which is contained in the unit will break down oxidizers in the water column that would otherwise lower a fish’ immunity ,this aspect is often missed as many only focus on the germicidal/algaecidal properties of UV Sterilizers.

UV Sterilization is also effective for controlling suspended algae (green water) in ponds (along with proper filtration such as Veggie Filters/pressurize filters.

Relationship between UV and Water Flow/Contact

This is easily the most important simple aspect of proper UV Sterilizer set up and all the gimmicks will not help a poorly installed UV with high flow rates of water passing through. In fact this is where most UV Sterilizers installed in ponds fall well short as pond keepers will place for instance a 9 watt UV with a 1000 gph pump which is 2-4 times the effective flow rate for a pond installation (often as per very poor directions by the manufacturer). This problem is also common among reef aquarists with high flow rate sump pumps attached to UV Sterilizers incompatible with the flow rate, resulting in the common and incorrect statement that “the UV Sterilizer was useless”.

Admittedly flow rate is a generalization expressed to simply mW/cm2 that is absorbed/transmitted to pathogens/algae (please read further in this article for more in depth explanation of UVC Penetration/mW/cm2). I use this method as simplified method that has tested well over the years in my applications of UV Sterilizers. Obviously there are other factors such as distance from the UV wall, water turbidity, quartz sleeve cleanliness, UV bulb condition/age, and more (again that are explained in this article).

As well many UV manufacturers will over state their UV Sterilizer abilities as per maximum flow rates (although this does not necessarily make such a UV Sterilizer a poor/inferior product as some other web sites claim, The simple calculations provided here to make your choice, not exaggerated claims by many UV manufacturers).

• The key to success is CORRECT water flow, cleanliness of the bulb and/or quartz sleeve, water particulates and water temperature.

*Generally for bacterial control (& many virus) a flow rate of 20-25 gph per watt (75-95 liters per hour, per watt).

*For algae control, 40 gph (sometimes as high as 50 gph) is effective to maintain effective exposure for effective UVC sterilization/radiation (depending on model UV design).

Admittedly this is a VERY basic and simplistic rule, with other factors such flow design, interior wall gap from UV bulb, & even actually output of UVC per watt.

*The design of the unit should only allow a gap of .3 cm or less between the bulb or quartz sleeve and the wall of the unit for effective contact and temperature.

This is where canister aquarium and pressurized pond filters (such as the Aquael, Nursery Pro, even the newer Via Aqua) fail miserably as there is too large a gap and in general a poor flow design around the bulb/quartz sleeve (as well as flow rates far exceeding UVC bulb wattage capabilities)

• When figuring the flow (gph) of a water pump, consider the flow of water AFTER it passes through the UV clarifier and reaches the aquarium or top of water feature in a pond. For instance water pump or filter rated at 400 gph at 0 head pressure & 6 feet maximum head pressure (which is how all pumps are rated), will likely only push about 200 gph after being lifted 3 feet from a sump or up a water feature.

For a positive check of flow rate, simply use a stop watch (many cell phones have this feature), and place a container under the outlet. For example if one gallon is filled within 10 seconds, this is 6 gallons per minute or 360 gph. Many persons are surprised how slow their pump actually is after applying head pressure.

Some pumps or filters lose head pressure more quickly than others (such as the Hagen Fluval), while other pumps are specifically designed to maintain higher head pressure over greater vertical distances .

Size of pipe/tubing on water flow:

Another consideration is the size of the PVC pipe or tubing coming from the pump. For instance a pump with a 1 inch outlet port that is rated at 2000 gph (for 0 head pressure) will likely not have an output of 2000 gph if the pipe/tubing used is ¾ inch or less.

This same thought goes for the UV Sterilizer itself, in fact the Custom UV I have built only uses ½ inch hose barbs so as to restrict the flow to under 350 gph which is the maximum effective rate.

Time; Generally a UV Sterilizer is best run 24/7, as this will provide the best Sterilization, Algae Control and Redox improvement. In Ponds this is particularly important as it can be difficult for a UV Sterilizer to keep up with algae growth during peak sunlight hours, while nighttime allows for a UV Sterilizer to “catch up” with algae spores. In Redox balance, a UV run constantly will provide a more stable balance.

There are exceptions though; many in Reef aquariums do not run a UV during certain hours (often using a timer) such as feeding micro planktons.

A UV Sterilizer should be turned off when certain antibiotics are added, when seeding tanks with established filter media, or Autotrophic or Heterotrophic Bacteria are added for bio waste composting or cycling .

FACTS (& MYTHS) ABOUT UV STERILIZATION;

Here are few things UV Sterilization will NOT do:

[1] UV sterilization will not cure infected fish of bacterial or fungal diseases. A UV can aid in cure by killing bacterial pathogens in the water column and fungal spores, also by improvement of the Redox Potiential (which is much more important then many realize based on scientific research) and general water quality.

[2] A UV sterilizer will not kill ich trophozoites already on the fish (but then medications don’t either), but UVC can again slow the spread of ich tomites in the water column (but usually not out right kill ich tomites). However by water quality improvement (such as Redox Potential) and lowering of pathogenic bacteria, the fish has more natural resistance to fight Marine Cryptocaryon or FW Ich.

[3] A UV sterilizer will not kill beneficial bacteria such aerobic bacteria, as this bacterium is effective when attached to a surface of high water flow such as the sponge of a sponge filter, not when in the water column. In fact relatively new scientific evidence shows nitrifying bacteria to be sticky and adheres to the surfaces like glue this is why the myth of UV Sterilizers killing beneficial bacteria is just that, a myth. It still may be best to turn off a Sterilizer unit when introducing bacteria in liquid form to seed a new aquarium.

[4] UV Sterilization will not remove or destroy algae growing on tank or pond sides, rocks, decorations, etc.

[5] UV Sterilization will NOT kill off copepods and other small life forms in a Reef or Nano Reef Aquarium.

This is one of the more laughable myths about the use of UV Sterilizers in reef aquariums as these copepods live at or near the bottom of live rock piles (making a pile with small pieces is best for copepods), they are not active in the water column. If properly installed, the UV should have at least a fine pore sponge filter media as a pre-filter, which will further stop the “ingestion” of these and other minute life forms (the UV benefits as well by being more efficient).

What is interesting about this myth is that many who spread this misinformation use filters such as the Ocean Clear Micron Filters systems (which are excellent micron filters), these filters will filter out any copepods that get caught up in the water column and “sucked” into the filter. As well even “pods” that do manage to find their way into the UV Sterilizer are rarely killed due to size as the typical flow rate of 20+ gph is not low enough to kill them (you would need at least 10 gph per watt, which I do recommend running a UV Sterilizer at flow rate of under 10 gph per watt for this reason).

The bottom line here is that I have maintained MANY Reef aquariums with UVs with growing copepod, anemone and other creature populations. Honestly this is one of the worst urban myths in the aquarium hobby about UVs (mostly spread on the internet in misinformed forums which never conduct or read scientific evidence to back up these absurd statements). The only truth to these statements is that UV Sterilizers can destroy some microscopic food sources needed by some of these organisms (usually planktonic algae, although timers that turn the UV on during certain hours is an easy remedy for this possible problem).

[6] UV Sterilization NOT remove minerals from aquarium water, however UVC Sterilization will also aid in the removal of oil based (carbon based) pollutants.

[7] The use of Ultraviolet Sterilizers will NOT lower fish immunity, in fact from my many controlled studies, the opposite is true. Although the exact mode is theoretical, evidence points towards improved overall Aquarium Redox being at least part of the reason.

[8] UV Sterilization will NOT make up for poor aquarium maintenance practices such as over crowding, over feeding, inadequate filtration, poor cleaning practices, improper water parameters, and more.

This point is likely the cause for anecdotal statements that fish coming from tanks that had UV Sterilization, then are placed in a tank without an Ultraviolet Sterilizer resulting in “losses” may be dealing with (besides the above point of improved immunity, which will be lowered after transfer). Often an aquarist (I have also performed this as well for studies) will rely too much on the Sterilizer/Clarifier for water quality, clarity, etc., as a UV Sterilizer will often keep a tank clear and healthy in appearance even when correct water changes, mineralization, etc. are not performed. For this reason the fish may not be has healthy as they should since a Sterilizer should NEVER be relied on as a replacement for good aquarium maintenance practices. Along this same line of thought, often aquariums maintained this way will have low KH and falling pH which can result in osmotic shock and even death when transferred.

a good UV SIZING LINK .

** Extracted from americanaquariumproducts.com **

[Harlequinmania]

Hydrometer

A Simple instrument used to determine specific gravity, in a sealed, graduated tube, weighted at one end, that sinks in a fluid to a depth used as a measure of the fluid's specific gravity.

Refractometer

A Refractometer is a simple and easy way ofaccurately measuring the specific gravity (salinity) within your aquarium and should be used by serious marine aquarist to get the most accurate reading of salt levels in their saltwater aquarium.

The refractometer works on the principle of refraction of light todetermine the salinity and is very accurate but also very simple and robust,unlike good quality glass hydrometers which are easily broken.

Light enters the instrument at one end and passes through a sampleof the aquarium water which causes it to be refracted, (bends the light),depending on the salinity of the water. The refracted light is reflected off ascale inside and can be viewed through an eyepiece on the opposite end of theinstrument.