Falling PH in vinyl AGP with swcg

[AusPhil]

Test overview from today CC is 0


The solar cover on and has been for about 14 days now as the weather has been variable and not really conducive to having a swim.
The SWCG was off for about 5 days and has been back on for the last 4 @ 10% for 6 hours seems to be holding FC at the upper end of the range with ease
We have had around 5" of rain that equates to about 15% of the pool volume of nice fresh rain water and that matches the fall in TA/CH
The borate number is purely based on additions and will have been diluted as well over time.

My concern is that the PH has fallen from it's quite normal 7.6 -> 7.8 readings i get with the swcg running and the cover on to barely 7.2
PH readings taken with calibrated digital meter in a completely consistent manner from test to test.

I'm currently assuming that the drop in TA isn't helpful in this......

Thoughts please

 

[Jimrahbe]

Phil,

What did you add to cause the TA to drop to 50? Fifty is the lower end of what we call "ok"... I would not let it drop below 50.

Accurate or not, I'd test the pH with a color match kit, just to make sure it somewhat agrees with your meter.

Thanks,

Jim R.

 

[AusPhil]

Jim,

absolutely zero chemicals .... just the aforementioned fresh rain water. The dilution volume has been enough to,explain most of the drop considering I’m doing the 10ml sample test and I’ll be raising the TA today.
i am surprised a little that the PH basically fell to the lower end of the range with the SWCG turned off or on minimum production
now I think about it, with essentially nothing happening if the rainfall was even slightly acidic that would easily explain the fall in PH

re the drop test, I’ll have to let the FC fall some more and give it a try... never been even vaguely comfortable reading the CCL kit he test

 

[Leebo]

Looking at the logs it appears the pH has been rock solid. I wouldn’t tinker with anything without another test and question the results.