Is it possible to raise TA and lower pH?

[dave18]

Hello all!

I had previously gotten my pool "balanced" and with a pH level of 7.5. Everything looked and felt great.

However, lately I've been having some mild eye irritation and the water tastes a little different to me. It's hard to describe the taste, but it's unpleasant, almost like a faint taste of crushed aspirin.

I tested the following levels:

TA = 70, CH = 200, pH = 7.8, water temp = 67 degrees F <== EDITED (76 was a typo)
SI is between 0.0 and -0.1.

So the water is "balanced", but the pH is a little high. I'm thinking that's the cause for the eye irritation. But if I add acid to lower it, won't that also lower TA? The TA itself seems to be a little on the low side. Most things I've read say to target about 100.

So I'm not sure what to do. Add baking soda to increase TA or add acid to lower pH?

Thanks for any help. In general, is it possible to raise TA and lower pH at the same time?

-Dave

 

[dmanb2b]

It possible by adding acid and follow-up with Baking soda to adjust TA. That said, hold off on adding baking soda until TA drops below 60. You may find 60 on TA is your sweet spot to better lock in PH

 

[chem geek]

Most things I've read say to target about 100.

And where did you read this? If you are using a hypochlorite source of chlorine such as chlorinating liquid or bleach (or Cal-Hypo or lithium hypochlorite) or if you are using a saltwater chlorine generator (SWG), then the TA recommendation in the Recommended Levels of the Pool School does not say anything about 100 ppm. It implies an average 80 ppm for non-SWG and 70 ppm for SWG pools. As noted in the previous post, you can go lower if you find the pH is more stable, but I doubt that the pH of 7.8 is causing eye irritation.

 

[257WbyMag]

For what it's worth, my pool TA likes to be 60 to 70. All I really ever need to do is add acid to lower the pH. My TA stays where it likes to be.

 

[JamesW]

A pH of 7.8 should not cause any eye irritation. The most likely cause is chloramines.

What are your readings for FC, CC and CYA?

What type of chlorine are you using?

What chemicals have you added in the last 30 days?

Also, your calcium level is a little low for a concrete pool. Is the pool painted?

 

[dave18]

Thanks for all the replies! Based on the great responses I got here, I did a little more investigating and am now looking in a new direction. So, thank you once again. This is my first pool, so everything's still a little new to me.

So, without adding any new chemicals, I noticed that sometimes the eye irritation is there and sometimes it is not. Well, the common factor is this: there is eye irritation when swimming soon after sweeping. Well, duh, right?

When sweeping these past couple of days, I'm noticing a lot of white powder clouds. I've been ratcheting down the filter time and I think that's the reason. I went from 24 hours/day to 12 to 8 to 6 to 5 to 4. I waited a week between each time reduction. The turnover time for my pool pump is 6 hours. So, it's looking like either 4 hours is too short, or I just need to sweep more often. I did get a little lazy on the sweeping there for a while.

I did test for CC, and it was at about 0.5 when it used to be at 0.0. After a lot of sweeping, the next day it was at 0.0 again. I also noticed that CC smell right after sweeping.

So, I think the white clouds were causing the eye irritation.

OK, that covers the basics of what I think is going on in this case, but you guys covered some other good stuff as well, so I want to reply to that.

dmanb2b, I will certainly hold off on adding. I didn't know the lower TA was acceptable. Since everything is balanced right now, it does seem best to not add chemicals if I don't have to.

chem geek, the Taylor booklet lists the ideal range for TA between 80-120. I think a lot of other sites just take the average of that (100) and publish it. But it sounds like many of you here are safely outside of that range.

And thanks for the recommended levels link! I had read that before and then just somehow forgot about it. I have plaster + bleach, and they recommend 70-90+ so it looks like I am good. But my CH is on the low side for that chart. So maybe I should look into using some calcium chloride.

257WbyMag, thanks, my pool may just want to be where it's at as well. I won't fight it as long as it doesn't drop too much!

JamesW, the only thing going into my pool is 12% available liquid chlorine. CYA was 50 the last time I tested, and I target 6 for my FC levels. It's usually somewhere between 5 and 7. I don't test for CC often, but when I do, it's usually 0. As I explained above, it was at 0.5 after sweeping recently.

I'm not sure what the previous owners of the house put into the pool. I do know they used chlorine tabs.

As far as I can tell, the pool is not painted. The plaster is not in good shape. It is grooved here and there and stained here and there as well. I didn't even know you could paint plaster. That looks like a great option, although I think the plaster on this pool is going to have to be replaced. It's something we're considering for next season.

Thanks again everyone! I think I'm going to increase my sweeping, but if I can't keep those clouds down, then I'm going to increase the filter time back to 5 hours. We'll see what happens.

-Dave

 

[JamesW]

I would not recommend paint. I was just wondering as I thought it might be relevant. The white clouds might be from paint or from deteriorating plaster. Increasing the calcium level would help reduce plaster deterioration.

 

[dave18]

The white clouds might be from paint or from deteriorating plaster. Increasing the calcium level would help reduce plaster deterioration.

I hadn't considered that. I will increase the calcium levels and see what happens.

Thanks for the suggestion!