on my filter?
Here is the history. I got the tank 4 months ago or so. It came with a submersed pump and filter. The filter portion (and maybe the pump - don't know - read on) was horrid. The water was piped above the tank to three different baskets. Each basket had one teeny tiny black filter thing that was about 3" by 6" by 1/4 inch thick. Needless to say that didn't work. I added the white floss stuff to each but even with that it would go green. I also added charcoal because of the smell (that worked!). Well, I have given up on this configuration as the water turned green (and no- not near a window) within three days.
Recently, I rigged up another filter - like a skippy pond filter - to go above the tank which I filled with scouring pads and a bit of the white floss using the pump I had (1200 liters/hour for a 190 liter tank). It waterfalls back into the tank through the charcoal and a thing of ammonia absorbing stuff. Still, the tank is turning green. It is a bio filter basically, so I have left the filter bucket alone although I have backwashed it a few times (read, every time I turn the pump off it empties because of gravity). I recently stopped feeding the greedy monsters in there so to reduce the bio load on the filter so we will see how that helps.
Today I did about an 80% water change (with conditioner) and I always add bacteria when I do any sort of water change. I don't know how long this will keep it clear. How long should I wait until I pronounce the filter I rigged up a failure?
And since I know it will be suggested. My tank is 40 gal for two 2 inch turtles. I am trying to re-home one of them (so far unsuccessfully) so I do not want to buy a bigger tank yet. We also may be building an outside pond (still working on convincing my husband that this is a good idea) so I don't want to invest in a bigger setup. No, a canister filter is not an option as there is no space anywhere near the tank to put it. The only space I have is above the tank.

