# API Ph TEST SOULTION vs. Ph meters



## Jaybird1 (Feb 9, 2015)

When I first bought my aquarium I new I needed to monitor my Ph. So while I waited for my tank to arrive I bought a Pinpoint Ph meter along with calibration fluids. Then I bought a CO2 injection system that included a Milwaukee Ph meter that went inline with my return filtered water and monitors and controls the amount of CO2. 

I also thought it a good idea to get API test kit that included a varity of tests . The kit included of course Ph plus Ph High. The expiration dates for the test fluids is 06/2020.

After carefully calibrating the Ph meters they both read the same PH of 7.0 within a + or - 0.02 Ph. I figure that is close enough. I use the Pinpoint as a backup to the Milwaukee about once a week, so the probe is not kept in the tank 24/7. 

But when I use the API test Normal Ph solution is showing 7.2 to 7.6 and the High Ph solution reading is < 7.4 . Note before adding API test solutions to the test tubes I carefully rinse out each tube with tank water a couple of times.

Can anybody explain the discrepancy or could Kh be effecting the API test solutions? :roll: 

Just a note here I also have Ph probe cleaning and storage solutions.


----------

