ph raised quickly, should I raise TA?

[skurys]

Hi all, I for the past couple days have been trying to get my chems in line.

The other day I put in about a liter (1/4 gal?) of MA to correct my 8.2+ ph. I tested a few hours later and it was back in range, about 7.4. Then I checked the next day and it was back above 8.2 again!

I put in another 1/4gal today and its back to about 7.4, just wondering is it normal it would rise that fast? Do you think I am out of the woods or should I raise my TA perhaps?

I have a pool test kit that does pH,FC, and TA as its the only thing available to me at the moment.

Current values are:

fc: 3
ph: 7.4
ta: 70
cya: 20 (dont have a test for this, but pool store tested it to be 0 and i added about 20 ppm's worth recently)

 

[Bama Rambler]

Is there a lot of aeration going on in the pool?

I wouldn't raise the TA if the pH is steadily raising. If anything I'd allow the TA to lower a bit more.

 

[skurys]

No aeration, I have the jet pointed down and still a bit chilly for swimming in. Last time I added MA the ph jumped back to 8.2+ within 24 hours. Not sure what would be making it rise that fast, I was at least hoping the ph would be a once in awhile adjustment kind of thing and not requiring bottles all the time to keep in check.

 

[Bama Rambler]

Are you sure of your test readings?
If you're using strips your numbers could be way off.

 

[skurys]

Pretty sure, did them twice with the drop based kit from pool store, its an Olympic brand kit with 5 bottles in it, best I can get locally without spending 150$ for something online (tf100 apparently doesnt ship to canada)

 

[Bama Rambler]

What strength is the MA?

Adding a litre of 20º Baume MA would have lowered your pH but 1.56. It must be 10º Baume (15.7%).

 

[skurys]

It is 20 baume, but no way to know if the ph was really 8.2 or higher, so being at 7.4 would mean it was around 9 before?

 

[Bama Rambler]

Yeah. Just adjust it as it rises.

 

[skurys]

This morning its already back to 7.8 - 8, doesnt make any sense, is there a sticky somewhere that says everything that can make ph rise?

Its a small pool and sand filter so maybe if trichlor lowers ph it would help keep this in check, and the backwashing would help keep cya in check..

 

[Bama Rambler]

High TA or Aeration is normally what causes the pH to rise. How are you testing the TA?

 

[skurys]

I took the best kit I could get locally (has oto, phenol, chlorine neutralizer, and 2 bottles for testing TA), I put 5 drops in (turns water blue), then 1 drop and swirl and repeat until it goes from blue to green, not including the last drop that doesnt change the color any further (as per tests instructions). Tested again and got 70 for TA.

My return jets pointed downwards...

Maybe the ph will stabilize if I add MA and aerate to get a lower TA, ~50?