Low PH 7.4

[Decopod]

Good evening, morning and afternoon good sirs.

As the title states I have low PH. As low as 7.3 over night. I don't have a lot of chaeto. I ran an airline from outside for about 2 days no PH change. I changed 20L of water, twice. I have a slow drip of Kalkwasser to refill evaporated water. I use 2 tsp of Kalkwasser for 5L(just over 1gallon) my total water volume is 100L

Any advice?

 

[marlinmon]

Here are my numbers. I live in an apartment, and despite a large CO2 scrubber, I see low ph consistently. My SPS does not seem to care much about ph. I do, however, keep my other parameters in-line.

 

[Oldreefer44]

What are you using to measure it?

 

[Decopod]

What are you using to measure it?

Digital meter and a test kit

 

[PDR]

What meter? When was the last time it was calibrated?

 

[MSB123]

What meter? When was the last time it was calibrated?

Yes. I was seeing this as well, but then I calibrated my probe and it was fixed.