pH Spiked, not sure why

[ftw]

Came home today and tested to find a pH spike from 7.4 two days prior, where it had been consistently, to 8.0 tonight.

5:30pm:

FC 3.5
CC 0
pH 8.0
TA 100
CH 370
CYA 85

(I repeated the pH test on samples from multiple locations and cleaned all my equipment to make sure I wasn’t getting a contaminated reading. Still 8.0)

added 27 fl oz muriatic acid

7:00pm:

FC 3.5
CC 0
pH 7.3
TA 100
CH 370
CYA 85

added 60 fl oz LC 10%

8:15pm:

FC 8.5
CC .5 (less? Very light pink)
pH 7.4
TA 100
CH 370
CYA 85

using a k2006.

i haven’t had any other issues, I let the FC get a little below normal yesterday.

 

[JamesW]

Your TA is a little bit high, did you add bicarb recently?

Are you using the fountain or is there other aeration?

 

[ftw]

Last time I put bicarb in was a month or so ago. I was on tabs (I’m new!) until switching to LC around that time and was fighting low pH.

i have a fountain and two spillways from the spa that are constantly flowing.

 

[Gene Clean]

Due to your pool size, the fountain and spillways will definitely increase your pH. I'm honestly surprised your TA isn't lower, due to the need to constantly add acid. If you don't think 8.0 is right. I suggest taking a test of your fill water, and compare.

 

[ftw]

The need to add acid is brand new as pH has been pretty stable and always on the low side. I’m wondering if using pucks previously was suppressing rise cause by fountain and spillway.

In in the last few days there’s been a constant climb in pH. I didn’t have to add any acid in the first month of switching to LC but it seems now to need to be a part of the regular regimen.

 

[ftw]

pH was back up to 8 again today, just 3 days after it happened the first time. All the other readings are the same as before.

 

[mknauss]

I would suspect your TA level hit that point that the pH rises quicker with the aeration.

You can lower your TA. See Pool School - Lower Total Alkalinity

 

[ftw]

Thanks mknauss. Am I right in understanding just adding MA over time will lower TA as long as I don’t do anything to increase it? And 60-80 TA is where I want to be?

 

[mdogan]

keep watching PH, do not focus TA...when PH got stable TA will be....
It may take time....Just keep adding MAcid..patiently after sometimes you will see the color of PH will never changed

My PH 7.8 and TA is 60 ; even with waterfall etc...it is stable...