I recently tested again and got a ph. of 8.2 and 10 ppm nitrates I tested the source water and got ph7.4 before and after degassing the source water with no ammonia nitrites and nitrates. I am still not sure what is happening to the nitrates as they should be much higher with the stocking levels and the timing of water changes on this tank. But it is working so I am not going to fuss too much over it. it is filtered by a pair of sponge filters each sized for a 120 gallon tank.