| Ok---
There are two types of filtration. Mechanical filtration and biological filtration.
Mechanical filtration is usually meant to remove something from the water. I.e. a filter bag or filter floss. Even a protein skimmer would qualify in this regard.
Biological filtration is to help the Nitrogen Cycle (I.e. turning Ammonia into Nitrite into Nitrates).
There are some filters that do a little of both. For instance filter floss that isn't cleaned regularly will develop bacteria's that will also perform the first two steps biological filtration. The problem is that a dirty filter floss can never remove nitrates.
Sand beds will perform both types of filtration. They house bacterias for biological filtration. They also offer Mechanical filtration in the sense that eventually the critters detritus has to go somewhere.
LR can help biological filtration as bacteria live on and in it.
Technically, a BB is the lack of a substrate and not a filter. However, bacteria can and will live on it.
This is a great thread. I definately want to have some input on it. It will take me a couple hours---I have to get something out the door right now.
Rock on guys. |