Great site! Just got my TFTest kit and I am having trouble reading PH. Overall, it is pink and I think it is probably around 7.6 to 7.8 or higher, but it doesn't really match up well with any of the colors on the chart because it is so faint (It's definitely not yellow, and not purple). Also, depending on the angle that I am holding the test cylender, it seems to be a different shade of pink! Maybe I am just slightly color blind???
If I were to add more than 5 drops of the phenol red (to try and make the solution darker), would that also skew the numbers?
I have been reading for a while and from what I have gathered, it looks like I should add some acid to lower the PH (if it is indeed 7.8 or higher). Will adding acid also lower the TA?
Here are my readings:
PH 7.6 - 7.8 (not really sure)
CA 400 (We have very hard water here. I have a vinyl pool, so I don't think CA is too important.)
I also know my CYA is a little on the high side, but is it anything to worry about right now?
Slightly off topic, I tested my tap water as well and got the same PH of 7.6 - 7.8 and also got a FC reading of 1.5! I then tested my RO water and the PH was yellow, indicating 6.9 or less (but the CL was 0). Does anyone know if an RO system can cause this much of a drop in PH?