AIRBORNE POLLUTION: Thiel
Many toxic compounds can enter the aquarium water from the surrounding air and, if they are not removed by some form of filtration (chemical) or regular partial water changes, they will build up to levels that may be just noxious enough to keep your tank in a drab looking state, or in a depressing looking shape.
The quantities present or the types of pollutants may not be of a toxicity level that kills fish and invertebrates quickly, and thus hobbyists do not pay any attention to them. In fact, in most cases hobbyists do not even suspect their presence.
It is, usually, only after hobbyists have exhausted all other methods and possible causes of pollution, and are at a total loss to understand what is going on in their tanks, that someone may suggest airborne pollutants. This is because when you have tried every method recommended by books and talked to pet stores in your area, you may start asking questions by calling around to manufacturers, reef specialists and so on. The latter may have a wider experience with this form of pollution.
These airborne compounds, which include fumes from paint, compounds used around the house to kill flies and insects and such, kitchen fumes, nicotine from smoking, etc. can all be removed easily from the water as long as adequate chemical filtration is used. Again, Poly Filters or very good quality activated carbon are the answer.
Besides entering at the air and water interface, these compounds will also enter the water because your air pump pushes ambient air into the tank, or into the filter, or both. If that air contains pollutants, the latter will end up in the water.
Because most of these pollutants do not cause instantaneous reactions, they are often overlooked. In fact, it does not even occur to most hobbyists that the air in the room where the filter and/or the aquarium are placed can be a source of problems.
