So I got to thinking today, exactly what good does an undergravel filter do? The only thing I can think of is that it will suck up all the debris in the water and provide circulation and oxygen. However, what about the ammonia and nitrates and such? It can't possibly filter that out, can it?
I have been using one of those discard-a-filters in my 2.5 gallon tank for my betta, Moe, but it's time to replace it and since my tank came with an undergravel filter I was just going to set that up instead. The main reason why I want a filter at all is to provide proper circulation so that the tank is heated evenly.
But, it just got me wondering if I would still need to change his water the same as if there was no filter in the tank at all. Does anybody have experience with undergravel filters?
