started a sump description
anyone want to add to it?
A sump is an extra water area usually set up underneath an aquarium that will increase the total volume of water in an existing system; here you can place extra filtration media, equipment, such as a top up system. a skimmer, calcium or nitrate reactor on a marine system or heaters in a tropical setup. Sumps can be plumbed in inline via a Siphon Overflow box, or bulkheads in pre-drilled aquariums, a sump can be as basic as an extra aquarium, a large plastic container, or as part of a more elaborate wet/dry trickle filter or refugium. With some basic plumbing work, a sump can be installed to most tanks to provide many benefits.
The basic principle of a sump is to take water from your tank through a siphon or bulkhead to the sump, generally pass that water through a series of compartments filled with filter media then return the water via a pump back to the tank.
As they increase the total volume of water in your system sumps can help keep your water parameters more stable and less prone to fluctuations. Sudden changes and the concentration of chemicals such as nitrite and phosphate are more evenly distributed; just remember that proper maintenance and regular water changes are still necessary as you are dealing with a closed system.
Sumps provide an area to add extra filtration to your aquarium and can incorporate a variety of advanced filtration systems. Some of these include a wet/dry trickle filter where the water is dipersed over layered filter media in a column and trickles down through it to a sump area. Usually filter wool is the first layer to stop any large particles or waste food going through the filter
A trickle filter is an aerobic filtration method, this means the bacteria present only occur or live in the presence of oxygen. The more oxygen saturation it gets, the better it functions, When the water falls through the holes of the drip or trickle plate then drops onto or over the bio-media it allows for maximum oxygen saturation of the water.
Jenniferh added
The conversion of ammonia and nitrates is dependant on aerobic conditions which support the nitrifying bacteria nitrobacter and nitrosomonas - the more air you have, the better these populations can function. Anaerobic filtration is also useful - aerobic bacteria convert nitrates into free nitrogen gas. I found a good schematic diagram which helps to illustrate the point.