14.1 INTRODUCTION:

In an effort to further sophisticate their systems, German hobbyists innovated the hobby in 1986 and started building and selling pressurized acrylic cylinders that could be used for the purpose of introducing air and ozone, air on its own, or carbon dioxide, in a manner that had not been tried before, but seemed to give good results after a period of testing and adjusting the design: under pressure.

The first reactors to appear in stores were oxygen reactors, soon to be followed by ozone and carbon dioxide ones. Hobbyists responded enthusiastically and soon such reactors became part of the normal equipment used by the more advanced hobbyist, both in Germany and other European Countries.

During a 1986 visit to Germany I saw these reactors at Nollman Aquaristik, in Bielefeld, and decided to import some of them into the United States, convinced that they were an important addition to the reef tank, and that the reef tank would benefit from their use.

Since that time we have gone from importing, to building them, after having changed the original design and added gauges to some of them. Testing determined that water distribution was more important than had been originally thought, and that pressures of 0.1 bar (about 1.5 PSI) did not give as good results as higher ones. After all modifications were made, my company made them part of the wide range of products we offer, and that are mostly used on reef aquariums and some also on freshwater plant aquariums.

We subsequently also introduced a series of more advanced reactors to automatically adjust the carbonate hardness, add calcium carbonate, and offer the hobbyist the ease of using chemical filtering media, and nitrate removing compounds, in a canister format that could be run in conjunction with the main water supply.

All these reactors are described in this section. Many are available from specialized companies such as Marine Technical Concepts and Route 4, and all can be ordered from my own company.

Because of the unique nature of some of them, not every hobbyist may have a need for each of these reactors though. Study your system, determine what you are trying to achieve, take a close look at your water chemistry parameters, evaluate whether the equipment that you are now using can do the job for you, and if not, decide on which one(s) you may want to add to your water management system.

When going beyond the basic four filtration methods discussed so far, plus pretreating the water used to fill and top off the aquarium, the word filtration does not seem to accurately describe what the hobbyist does, anymore. I therefore prefer to use the terminology "water management system".

Important note on pressurized reactors: to operate such a reactor efficiently the air, or the mix of air and ozone, or the CO2, must be replaced continuously. If such were not the case, the amount of oxygen, respectively ozone and carbon dioxide, would soon be exhausted. All that would then happen is that you have a reactor that operates at a higher pressure than normal, but no more transfer of the desired gasses occurs, and the reactor is not achieving anything for you.

Reactors that are properly adjusted, therefore, always show a stream of both water and bubbles coming out and mixing with the area where you return the effluent. If this is not the case you must further adjust your reactor. Because such can be noisy, it is best to submerse the hose attached to the "out" side of the reactor. This will greatly reduce the noise, if not eliminate it altogether.

If all the reactors you use, or at least most of them, can be fitted into the trickle filter that you operate, you will have a more streamlined system that requires considerably less space. This is a plus because space underneath the aquarium is limited. Such is possible with all Platinum Series Trickle Filters.

14.2 OXYGEN REACTOR:

A reactor used to inject oxygen under pressure into the water, called an oxygen reactor, is nothing more than a cylinder, usually of acrylic material, filled with a medium that disperses the water efficiently, in which air is blown at the same time as water is forced in.

Providing your air pump is strong enough, and providing your water pump can handle the back pressure, one can increase the internal pressure by adjusting both at the same time, and using a gauge to determine what, in fact, the pressure inside the reactor is.

Because of the over-pressure inside the cylinder, air - which contains 21% oxygen - is made to give up more of its oxygen to the water (the partial pressure of oxygen now being higher). This increases the dissolved oxygen levels of the water, and benefits the system overall.

The recommended over-pressure is 3 PSI, but I run my own system at 6 PSI and obtain better results. Approximately 75 gallons of water per hour flow through the reactor. You must determine what is best for yours by experimenting with various pressures, making sure that the reactor you are using can handle them. If not, it will blow out and a seam will "give" somewhere, creating a potential leakage situation.

14.3 OZONE REACTOR:

An ozone reactor operates on exactly the same principle as an oxygen reactor. Setting one up, and adjusting it is done in the same manner as well. Make sure though that the reactor you are using is certified for ozone use. Remember, ozone is a very strong oxidizer. Pay attention to the medium inside, and to the small fittings that are used to hook the air/ozone mix up to.

Instead of running such reactors at 3 or more PSI, I have found them to operate efficiently at 2 to 3 PSI, and run mine at that level. Again about 75 gallons per hour are flowed through the reactor. Experiment with yours, both the pressure and the amount of water you flow through, until you are satisfied with the result. Remember that ozone must be neutralized with activated carbon.

14.4 CARBON DIOXIDE REACTOR:

Because, to some extent, the amount of carbon dioxide that is required by your system is determined by the efficiency of the injection system itself, ensuring that such is done in an optimal fashion will save you many trips to the welding supply place to refill your CO2 canister.

CO2 reactors are not pressurized reactors in the same sense as the previous ones, except for the short periods of time when carbon dioxide is actually being released and mixed with the water. As a result, all they require is hooking up. Water needs to be brought to them, either by means of a bypass in the main water line, or by means of a small power head pump.

Because the water going through the reactor will itself create some back pressure on the carbon dioxide supply system, you will need to adjust the pressure reducer valve on your CO2 gauges to enable them to overcome that back pressure. In my experience 5 to 6 PSI is usually enough, but you will have to determine what works for you yourself.

Each time CO2 is injected into the reactor, the water level will diminish, and water mixed with CO2 will escape from the "out" side. When the CO2 supply stops, the reactor will fill itself with water again. Some hobbyists wonder whether such is the correct way for those units to operate. It is.

14.5 MOLECULAR ABSORPTION REACTOR:

Molecular absorption discs are chemical filtering media developed by Poly Bio Marine Inc. and sold by TAT under license, for use in this particular reactor. You can, of course, buy these discs from all of Poly Bio Marine's dealers, but without the special TAT reactor. Poly Bio Marine Inc. do sell another type of housing in which 12 or more discs can be placed, and that can be piped in-line with the main water flow. The modular TAT reactor fits into a compartment in the Platinum Series filter.

This highly efficient medium, also sold by Poly Bio Marine in the Poly Filter form which is probably known to most of you, is so efficient that I can not conceptualize a system that is running without them. If you are truly interested in maximizing the efficiency of your water management system, you must include these discs, or the Poly Filters, in your chemical filtration set up.

Poly Filters and molecular absorption discs do not leach any compounds they have absorbed back into the system, and progressively change color as they exhaust their absorption capability. This gives the hobbyist a clear signal when time has come to replace them. To prevent the discs, or pads, from acting as a mechanical filter as well, it is a good practice to pre-filter the water that goes to the molecular absorption reactor.