So you're barely at 10 x turnover, and that's assuming you didn't lose gph
due to head clearance of the pump.
I'd add a MaxiJet 1200, at the top, and angle it so it ripples the surface of the water quite a bit. That's going to improve gas exchange, which should prevent CO2
buildup over night, and thus reduce pH fluctuation from that.
I too would not put faith into the fastest/seatest kit.
Could the dKh
kit be Aquarium Pharm/Doc
Welfish? Basically where each drop equals 1 dKh
, and it starts off blue and turns yellow when you've hit the right dKh
of the tank?
If so, I've compared that 'cheap' kit to my 'expensive' seachem alkalinity kit, and they give the same figures...so I'd say if you've got that kit, then your 11dKh is probably correct (and a good level)