Guidance needed, 3 years using TFP and I am at a loss (Solved)

[jsnpckns]

I’m curious what you mean by this? The test should tell you whether its 9 or 10ppm, no probablies needed.

Over 10 FC, the pH is usually reading darker violet after a few seconds, like past 8. If I just let the FC drift down closer to 8 or 9, it reads lower without having added any acid.

So since it appears 7.8 and doesn't darken, I am assuming a 10 ml FC result of 10.5 is probably somewhere closer to 9-10.

 

[Bperry]

Over 10 FC, the pH is usually reading darker violet after a few seconds, like past 8. If I just let the FC drift down closer to 8 or 9, it reads lower without having added any acid.

So since it appears 7.8 and doesn't darken, I am assuming a 10 ml FC result of 10.5 is probably somewhere closer to 9-10.

You’re aware that high chlorine affect the pH test? Its not that the FC is something other than the test result its that your pH test is testing higher than it actually is when the FC is over 10ppm. Thats why TFP tells people not to test the pH until the FC is kower than 10ppm.

 

[jsnpckns]

You’re aware that high chlorine affect the pH test? Its not that the FC is something other than the test result its that your pH test is testing higher than it actually is when the FC is over 10ppm. Thats why TFP tells people not to test the pH until the FC is kower than 10ppm.

I understand that. That is why I was commenting on the pH. Usually over 10 FC, the pH has never read lower than 8. I know the pH is not right, which is my point. The pH reading a solid 7.8 with 10.5 FC just made me think the accuracy of the 10 ml sample I took was such that the actual FC might be below 10, given the steady pH which I know I didn't have to test, but I did, for that reason: an indirect indication of the +/- delta of the 10 ml sample accuracy.

 

[Bperry]

I understand that. That is why I was commenting on the pH. Usually over 10 FC, the pH has never read lower than 8. I know the pH is not right, which is my point. The pH reading a solid 7.8 with 10.5 FC just made me think the accuracy of the 10 ml sample I took was such that the actual FC might be below 10, given the steady pH which I know I didn't have to test, but I did, for that reason: an indirect indication of the +/- delta of the 10 ml sample accuracy.

Ok, Im not sure it works like that but not a big deal. Are you not logging chemical additions? If you’ve been adding acid to keep the pH down, your TA will come down as well and slow the pH rise. Thats a more likely reason for the pH reading lower than expected.

 

[jsnpckns]

Ok, Im not sure it works like that but not a big deal. Are you not logging chemical additions? If you’ve been adding acid to keep the pH down, your TA will come down as well and slow the pH rise. Thats a more likely reason for the pH reading lower than expected.

I log all my chems. I didn't log the swg separately, just logged the changes on the panel until I got advice in this thread to track it as chem addition to make it easier to see loss/gain.

Last time I added acid was last year to get my TA back down between 50 and 60 after having to refill a significant amount of high 100-150 TA water after draining for a quarter sized repair. It was about a third of the pool. As long as it rains occasionally and I don't have to do big fills, my TA stays around 60 and my pH doesn't approach 8.

I found out the first summer owning this pool that I didn't Want to have to add acid every week or two, fighting the rise from the swg. So I learned reading TFP how to push the TA down, what was causing the rise, testing my fill water etc, so I don't have to use acid but rarely.