PH testing never the same

[countryfan05]

I use the test kit from Aquarium Pharm. with the drops but everytime I test my ph it is different. I can use the same water from the same cup in two tubes, clean the tubes with the fish water and test and one will be yellow 6.0 and the other green 6.6? Sometimes I even get a blue 7.6 reading. Any suggestions?

[malkore]

How old is the kit? should have an expiration stamped on the reagent bottle.

its not uncommon for water with little carbonate hardness to have mild pH changes between morning and evening, but two samples tested at the same time should be the same, provided there was no user error.

make sure you gently shake the reagent bottle to mix it, and make sure you hold it perfectly vertical so the drop sizes are consistent.
make sure your hands are clean of any soaps, lotions, chemicals, as that could contaminate the sample and cause false readings.

[Meredith]

also don't touch the rim of the tube or the inside of the cap

[countryfan05]

The kit is about 6 months old, I will try your suggestions, thanks