How soon can I re-test?

[Linkterfur]

Sorry if this is a repeated question as I'm sure it is.

But how soon can I re-test my water for CH and CYA after I've diluted it with tap water? I've been told 15 minutes for pH and Alk, but this apply?

 

[Richard320]

I would just make sure it's well mixed and test. A minute, maybe?

Diluting with tap water is okay for CYA testing, but you need distilled water for the CH dilution.

 

[257WbyMag]

On the heels of what Richard320 said, the reason that you need distilled water for CH test dilution is because tap water generally has enough calcium in it already to skew test results. Deionized (distilled) water has no metals to interfere and that is why it is best to use.