pH monitor question

[Dante]

Hello,

I just got a new hand-held pH Monitor. It shows that my tap water is 5.68 (which I don't think is possible) and my reef tank is 7.35. How far out of calibration can these things be?

 

[alexk3954]

I am pretty sure that you have to calibrate them yourself. It should have come with a solution with a marked ph that you use to calibrate the thing.

 

[Dante]

It didn't come with any calibration solution. I'll have to get some. I thought it would be reasonably accurate out of the box. Is it possible to be out by over 1.0 of pH?

 

[jdeets]

Yes, definitely. They can be off by several pH, before calibration.