Tale of two tanks
I have two dirted tanks set up, a 29 gallon and a 15 gallon. Both used the same bag of MGOPS. The 29 is capped with Eco Complete and the 15 is capped with a baked clay substrate. Both tanks have a little too much substrate but also have MTS. Water changes and top off for both are done with the same treated tap water. Both have been set up and running for about a year. While doing water changes tonight I checked water parameters for both tanks. I have not done this in a while as both had been in lockstep with each other from the begining. The 15 has ammonium of 0, nitrites of 0, nitrates of 5, ph of 7.6, KH of 7. This is what it has been more or less from the start. The 29 today has ammonium of 0, nitrites of 0, nitrates of 10, ph of 6.6, and KH of 2. GH for both tanks was not available as the test did not function correctly. Both tanks are planted, the 29 more so, and both are lightly stocked with fish. Any ideas as to the difference of the readings? I do prefer the 29's readings as that is what I was hoping would happen with the addition of the MGOPS.