Waste,

Thanks for the quick reply

Your statement about a previous test interfering with the results of the PH test are certainly a scenario. I have been following the procedure on the lid of the Taylor test kit, which has you checking for Chlorine and then PH. So I can certainly alternate the test sequence.

I have not been dumping the results of the Chlorine test back into the pool, and I thought I had been rinsing the tube before doing the PH test well enough, but maybe not enough

I will try doing the PH test first tonight, and then post the results here.

Once again, thanks for your help.
John