PH going up after KH stablise

Sherman · Jun 25, 2018

I have kh instablity for a long time. I try to maintain it at 7.5 dkh.
But it always slip to 7.0 or lower when I am busy . I am running a CR.
I need to dose KH daily beside the CR running.

Recently got myself a KH controller. And after 1 week find that it actually stablise around 7.5 +-0.5
But at the same time I find my PH move upwards from 7.7 to 8.5 over a period of 1 week.
Before running the KH controller it is around 7.4 to 7.9
And I need to run a CO2 scrubber and dose kalk daily to get that.
Now I had remove the kalk dosing after noticing the PH creeping up .
But the PH is still high at 8.5. Don't seem like lowering.
Is this normal? Must I bring down the PH to 8.3 ?
Hope someone can give me some pointer

Dr. Reef · Jun 26, 2018

what are you using to dose alk?

Sherman · Jun 26, 2018

I am dosing Aquaforest Component 2.

According to Aquaforest website Component 2 is
made up of Component 2+ contains: NaHCO3, F, I

Randy Holmes-Farley · Jun 26, 2018

That additive will not raise pH. I expect that if the alk is still around 7.5 dKH (as opposed being very high, like to 15 dKH), that the pH rise is testing error. I suggest you recalibrate the pH meter.

I'd also suggest that whether you end up believing the rise is testing error or not, the pH value of 8.5 is fine and not a concern.

Sherman · Jun 26, 2018

Randy Holmes-Farley said:
That additive will not raise pH. I expect that if the alk is still around 7.5 dKH (as opposed being very high, like to 15 dKH), that the pH rise is testing error. I suggest you recalibrate the pH meter.

I'd also suggest that whether you end up believing the rise is testing error or not, the pH value of 8.5 is fine and not a concern.

Thank You Randy for sharing. I believe the PH meter may be out. I will calibrate it

Randy Holmes-Farley · Jun 27, 2018

Sounds good.

pH 10 buffers can also drop in pH as CO2 enters as they get old, leading to the meter reading false high.

Let us know what you find.

Sherman · Jun 27, 2018

Randy Holmes-Farley said:
Sounds good.

pH 10 buffers can also drop in pH as CO2 enters as they get old, leading to the meter reading false high.

Let us know what you find.

Ok. Thank You Randy for the additional info