pH rapidly rising

[S1ngram]

We had our pool installed last year in June. My first season with the pool, I went through 3 gallons of MA. I opened my pool on April 18 and I am now (already) on my fourth gallon of MA. My return does not break the surface. The main way my water is getting aerated is by the wind. Right now, it's relatively calm at 11 mph, but we've had quite a few gusty days...sufficient to make waves in the pool and cause water to go overboard.

Is it normal to use this much MA?

My latest test results
FC-5
CC-0
pH-7.5
CYA-40 (recently added stabilizer so I expect this to go up)
TA-160

This summer I will be adding a SWCG and will be adding salt soon. What effect does a SWCG have on pH if any? Would I benefit from the use of borates?

 

[JVTrain]

Your pH rise is directly related to your TA level. Higher TA levels will lead to faster pH rises with aeration. Not sure how your TA got elevated, perhaps your fill water has high TA? Mine does at 120-140. I would test your fill water for TA to confirm. Need to keep maintaining pH with acid until your pH settles down, likely it will be somewhere between 60 and 90 TA.

A SWCG is another source of aeration, pH rise. You may find that your pH rise is more than without a SWCG but probably not alot. See the Recommended Levels and notice that a slightly lower TA is recommended for SWCG chlorination because of this added aeration.

Borates can help stabilize pH, based on feedback from many people here at TFP. Don't add borates until you have a handle on where your TA likes to live for your pool. Maintain your pH/TA for a while then choose to add borates or not. I see less value for borates for the purpose of pH stabilization for seasonal pools. Especially in my case (maybe yours) where fill water is high TA, needing to spend time adjusting TA after spring start up then adding borates again every year because of seasonal/closing drain of water and some of the borates with it.

Edit/Addition: Another large source of aeration is rain. I'm not sure if you've had much rain recently or if your pool is uncovered but rain is a huge aeration event. Rain water itself does very little to affect water chemistry, but the action of the water drops striking the surface thousands and thousands of times is a lot of aeration and can lead to high pH, dependent on TA, after a significant rainfall.

 

[S1ngram]

JVTrain thanks for your response. We have had nearly 3" of rain in the last 2-3 weeks. I don't know why I didn't think of that as being the cause. The fill water TA is really high. The TA test I ran last summer after filling the filling the pool for the first time was 230. By July 24th, I had gotten it down to 190. It's been 160 ever since I opened this year.

Handling MA is not at the top of my favorite things to do list. Are there other formulations of acids I can use or is liquid the safest?

 

[ping]

Liquid is the best option to lower TA. Once the TA gets lower the pool should settle down just like last year.

 

[chem geek]

Your TA will rise more slowly if you get a pool cover since evaporation and refill will increase the TA in your pool. So while you can certainly get your TA lower by adding acid and aerating, you may get frustrated with your continued rise in TA from the fill water. A pool cover will virtually eliminate evaporation.

 

[S1ngram]

I will need to work on the pool cover situation. I just don't use it. I think I'll do a little playing around with aeration and see how fast I can use that to help me drive the TA down. We are expecting rain in the next few days so that might help some too. Thanks for the responses.