Low PH

Alexander1312 · Apr 30, 2023

I am looking for some new fresh ideas on what could be causing my low PH. It no longer goes above 8.05 during the day (7.8 at night).

- Kallwasser dosing
- Alk 9.0 (Hanna)
- CO2 450-500ppm (Aranet 4 CO2)
- Calibrated Milwaukee and APEX PH probes

A couple of additional facts that could be relevant:

1. I had battled Dinos for months and had elevated Silicates (Diatom bloom). Dinos are gone now and their timing seems to be linked with the lower PH. While I had Dinos, my PH was often above 8.3 during the day. I stopped dosing silicates after the Dinos were gone.

2. I had two MP10s in a 26-gallon tank. One is currently for servicing and I am not sure if the timing of currently running only one matches the lowering of the PH. However, I am running the remaining MP10 between 50-60% and I thought two MP10s in such a small tank would be too much anyway.

Stephen Glover · Apr 30, 2023

I was in your boat and it turned out my pH meter went bad and was reading .3 lower than it supposed to. Try doing a titration Ph test and compare the results.

Alexander1312 · Apr 30, 2023

Stephen Glover said:
I was in your boat and it turned out my pH meter went bad and was reading .3 lower than it supposed to. Try doing a titration Ph test and compare the results.

Thank you. I am using two different PH probes (APEX and Milwaukee), both calibrated twice recently, but were still showing accurate parameters, so the low values I am receiving seem to be accurate. What is the titration Ph test and what is it trying to do? Thanks again.

Stephen Glover · Apr 30, 2023

Alexander1312 said:
Thank you. I am using two different PH probes (APEX and Milwaukee), both calibrated twice recently, but were still showing accurate parameters, so the low values I am receiving seem to be accurate. What is the titration Ph test and what is it trying to do? Thanks again.

I was referring to a simple Salifert or equivalent pH test kit. The odds of both being wrong are slim but not impossible.