Originally Posted by killavixen
why not use cannister?
The basics of FW aquaria are:
Fish excrete ammonia. Bacteria in the aquarium turns Ammonia into Nitrite, and bacteria in the filter converts NitrItes into NitrAtes. Nitrates build up and are removed through regular water changes (any freshies can come in and correct me here).
The basics of SW aquaria are:
Fish excrete ammonia and Dissolved Organic Compounds (DOC). Aerobic (oxygen-rich) bacteria convert ammonia into nitrites, and aerobic bacteria convert Nitrites into Nitrates and anaerobic (low-oxygen) bacteria (found deep in the live rock and at the bottom of a deep sand bed) convert Nitrates into Nitrogen Gas, which leaves the system naturally. Dissolved Organic Compounds break down into Nitrates, which are aslo converted by anaerobic bacteria into Nitrogen Gas, unless they are removed before
they break down. In one picture there is Marineland SeaClone Protein Skimmer. The Skimmer removes DOC before they break down by "charging" the molecules in the water to "attract" the ions of DOC (fish 'poop') and bringing them to top of the water column (of the skimmer) as they float to the surface. This rids the system of DOC and potential Nitrate builup before
it breaks down into more harmful forms.
Since canister filters by design create a buildup of Nitrates, they are detrimental to a marine system. Nitrates have a direct effect on Alkalinity, and can reduce it at a rate of 2.8 dKH for every 50 ppm Nitrate. Without a Deep Sand Bed, this Alkalinity cannot be replaced without supplementing. And since a canister produces
Nitrates, it can be exponentially reducing Alkalinity and be harder and harder to keep up with.
I don't use a canister. Won't even run it empty, as I am afraid that detritus and food will get caught in the mechanics and break down unknowingly...