Differences in pH Tests...

[dattia]

This week I ran out of the yellow bottle of reagent for my daily FC/pH test kit. I know these are commonly found, so I picked a new kit up locally (AquaChem). When I tested with the new kit, I was showing a raised pH (bright pink), so I added a little pH down. I have seen no change in my readings with this kit for 3 days now where it concerns ph... and up to this point, I hadn't really had any fluctuation in my pH.

I got out the old kit which still has some reagent in the red bottle. I used that to take another reading and it says that the pH is 7.5, which is pretty much where it's been all season.

I'm not sure what the difference in these two tests can be. Any thoughts?

 

[coffeegoddss]

Reagents have shelf lives, don't they? Maybe one is too old...?

 

[Bama Rambler]

What's your FC? Some pH tests are more sensitive to high FC than others and if you're runnign high FC it may be fooling the new test. You could add a drop or two of acid to a gallon of water and see if the new kit will see a difference.