I just test my water, my ph at first was 6.8, but I am fighting some algae and have added bleach to elevate my cl. So I assumed this was a false low reading, so I added a couple drops of Thiosulfate before my PH indicator and it read at 7.5ish, ok, so I went out and tested again the same way, but with 4 drops of Thiosulfate, the reading was 8.2, so now I have gotten readings from 6.8 to 8.2, I tried several more times with just two drops of Thiosulfate and got 7.6-7.8 consistently. Is this the actual reading or should I add something , if so, what?