I use Ben's PS-233 to test my own water. I have never had a problem with bouncy pH or TA. When I test I keep dropping the R-009 reagent until the colour stops changing. It goes from green to purple and then to red and then to a very pale red and doesnt move off of that colour. It goes to purple at about 6 drops, to red at about 8 drops and then to pale red at 10 or 11 drops and additional drops make no difference.

I thought I was to keep dropping R-009 until there was no further colour change. This always gets me to 100 or more.

Two different pool stores also tested for me this weekend - one said TA was 75 another said 80.

The one that said 75 said it was too low and that I needed to get some buffer in asap because my water was acidic and I would start stripping copper out of the heater and it would wipe out the heater. I suspect that this is not correct, given that this store also told me my pH was fine (7.8).

Anyways, looking for some insight on the home test vs. the two pool stores and which is likely to be more accurate and what, if anything, I need to do, ie. add baking soda to bring TA up?

Thanks.