I purchased a TF-100 test kit to test my hot tub's water. I have a few questions about the testing procedures.
First, should I let the water cool before testing?
Second, when doing the FAS/DPD chlorine test, the pink water turns clear, but after sitting for a couple of minutes, it turns slight pink again. I add another drop or two and it clears again. Should I base my result on the first time it goes clear, or should I count the additional drops?
Third, when testing for TA, I add the drops to the green water, and at a point it turns a dark purplish-red. If I continue to add drops, it turns more red. Do I stop when it turns from green to purplish-red, or add until it it is a true red?
Last, is the PH test in the blue box the best PH test available? I have a difficult time determining the ph level, it doesn't seem to match any of the color gradients.
Any advice you have regarding testing the water would be helpful.