 Re: Wet and Dry filter?
The primary task of a Wet/Dry filter is to provide biological filtration. Therefore, your Wet/Dry system could be the most important ingredient of a successful tank, whether you keep freshwater or marine animals. This is the process in which ammonia is converted to nitrites, then to nitrate. However, many Wet/Dry filters incorporate more than one method of filtration. Most have chemical chambers enabling you to store carbon or other resins. And, most have filter pads which help take particulate matter from the tank. These filters actually combine biological, chemical and mechanical filtration all in one unit. And, some have very effective protein skimmers, making them all-inclusive units.
Wet/Dry systems earned their name by the method by which they stimulate bacterial growth. A successful bacteria colony requires moisture, heat and oxygen. The temperature of your tank will provide the necessary heat for proper growth. And obviously, the moisture is taken care of by the water in your tank.
Each Wet/Dry filter uses its own type and grade of bio material. Most filters use bio-balls, which are spherical plastic balls which are hollow and have a netted structure. Other filters such as the CPR family of Wet/Dry units use a structure called Bio Bale, which looks like 'plastic hay'. The bio media is used to stimulate the growth of bacteria.
When the water enters the wet/dry filter from your tank, it is poured over the bio material at a high velocity. As the water flows over the material it mixes with the air, supersaturating the water. It is this mixing affect that contributes to the term Wet/Dry.
When the water is processed by the bio material, it enters the sump, which is simply a collection reservoir where the water awaits its return to the tank. In the sump, tank water is processed chemically and mechanically, and with a protein skimmer in some filters. Then, it is pumped back into the tank. The process repeats continuously, all day and all night
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