pH Results Interpretation Help

[gln826]

Hey all,

My pH value on my Apex has been steadily creeping up over the past three months or so. In October it was average 8.25 each day, now about 8.55. Although the first thought might be an increase during the winter months, I have to say that my house has been buttoned up for winter since around the middle of October, and before that, buttoned up for air conditioning.

So tonight I wanted to see if I was getting Apex probe "creep" (is there such a thing?), so I did a Red Sea pH test to see if the two numbers correlated. At the time of the test, the Apex said the pH was 8.66 and trending on a rise.

The hard part in this is the interpretation of the Red Sea result. What would you say this value is? It's certainly not 8.66, but it's a color that doesn't show up on the chart. I would say my result is more "purpley".

Thoughts?

 

[TheEngineer]

I don't know Apex, but I'm assuming it has a calibration setting right? You can get 7.0pH and 10.01pH solutions from the LFS (usually around $1 each) and recalibrate the probe to make sure it is working right. I'd expect an increase in CO2 over the winter with everything closed up and that would cause your pH to go down.

Do you dose anything? Kalkwasser perhaps?

 

[redfishbluefish]

You're not getting over 8.5 unless you're adding nasty stuff to your tank....or overdosing saturated Kalk. When is the last time you calibrated the pH probe. Try cleaning the probe by placing in vinegar overnight and recalibrating.

 

[gln826]

I dose RedSea Reef Foundation ABC+ and Vibrant only, although through the middle of November through the middle of December I was dosing 10 ml twice a day of H2O2 for cyano in my 90 gallon Reefer 350. Not withstanding the advice of calibrating the probe, how would you interpret that result? Whats the best way in the collective opinion for gradually lowering the pH?

 

[redfishbluefish]

If it was real.....which I doubt.....you'd bubble CO2 to lower pH. But, again, it can't get above 8.5 unless you're putting something nasty in there....or overdosing kalk.

You could also try just bubbling room air...especially in the winter in a closed house, it has more CO2.

 

[TheEngineer]

You could do the reverse of the CO2 test, I suppose. Tank a cup of tank water out of the house and run an air stone in it for 30 minutes. Measure the pH. If it changed, it has to do with the air in your house. I'm with @redfishbluefish though, I'm suspicious of your reading. That's why I suggested calibrating.