I am posting this for my mate who has a problem with his RTC. Its in a 6x4x2.5ft tank filtered with a FX5 and a 5x2x2 sump full of sponges and alfagrog. Now the past couple of days the RTC has been sitting under the return from the sump. This is powered by a 7000lph pond pump so quite a good current and lots of air bubbles.
He has tested the water and ammonia, nitrite are 0, nitrate very low (didn't give me an exact figure!), PH 8 (out of tap and normal for us) and hardness 7dh.
What can he do for the poor thing? In the tank also is a 20" Gourami which he says lays on its side most of the time and a 18" Banjar arowana.
I think they are being poisoned by something but the water parameters suggest something else? He took a sample to a LFS and they got it reading all ok as well. I suggested a little salt in the tank and moved his two 3000ltr powerheads to the top to create more aeration.
Any help and advice appreciated.