pH not rising with aeration

[P00LNerd]

I added some dry stabilizer to increase my CYA, and it dropped my pH from an already low 7.2 down to 7.0. I figured no problem, a day or three of aeration and I’ll have it right up into the mid-7’s, I’ve done it many times before, but this time progress appears to be much slower than I remember.

It has been 36 hours, and pH has only increased from 7.0 to 7.1, whereas memory tells me I should be seeing more like 0.3 ppm in 36 hours.

Aeration is done by a sprinkler head on one return, and simply aiming the other return up at the surface. I have the solar cover folded back in both areas, to expose the surface, but otherwise covering the rest of the pool, as we’re still seeing high 40F’s overnight (today was 47F low to 81F high).



I suspect my pump is running slower (for off-season) than other times I’ve used this trick, and having the cover over most of the surface is probably another factor, but which is likely the bigger detriment to raising pH?

 

[Mdragger88]

I would say the cover.
Aeration also takes time

 

[PoolStored]

cover over most of the surface is probably another factor

Big one.

 

[ajw22]

The cover prevents CO2 outgassing which prevents pH rise.

Aeration - Further Reading

www.troublefreepool.com

What Causes Aeration to Raise pH​

Anything that increases the surface area of the air-water interface increases the rate of carbon dioxide leaving the pool water. The outgassing of CO2 causes pH to rise.

Pools are intentionally over-carbonated both to provide a pH buffer and to saturate the water with the carbonate portion of calcium carbonate to protect plaster surfaces from dissolving. In other words, there is a lot more dissolved carbon dioxide in the water than would naturally occur in equilibrium with the air (though not as much as a carbonated beverage!).

As for why the pH rises, the easiest way to explain it is that some of the carbon dioxide in water is carbonic acid -- that is, carbon dioxide plus water makes carbonic acid -- so removing carbon dioxide is like removing carbonic acid. Removing an acid from the water makes the pH rise.[

 

[P00LNerd]

Thanks, guys! Cover will come off tomorrow, then. It'll be cloudy and raining the next 6 days anyway, so little to be gained from having the solar cover on.

Pool water is holding 69 - 73 F with cover on sunny days, which is great considering we were 59F - 61F water temperature a week ago. Daughter even went for a swim today, when we hit 81F air temperature mid-afternoon. But we won't be seeing much higher than 60F air temperature the next several days, no one will be swimming.

 

[Mdragger88]

Btw - with your ta above 100 the ph will rise anyway. No need to rush it. If you wanna leave the cover on to keep it comfortable for swimmers that’s fine too. Your ph is fine where it is.
It can be hard not to tinker but either way I wouldn’t sweat it too much.

 

[P00LNerd]

Well, yeah... I know 7.1 ain't bad. But that big red exclamation mark staring at me from the PoolMath Overview page just won't leave me alone, so I must drive it toward middle of range. Human nature.

I didn't have a chance to get a baseline this morning, but suspect it was still holding 7.1, as it has been the last few days. I pulled the cover off, and now just 3 hours later, it's already jumped to 7.3. A little rain pelting the surface probably helped with the aeration, as well.

I'm bummed that adding stabilizer didn't even nudge my TA a little, I think it's just destined to be forever high. I'm not sure how much that really matters, but again, those Darn red exclamation marks shout at me from the PoolMath overview page.

Psychologists could learn a lot from studying human reaction to PoolMath. Or conversely, the developers of PoolMath might want to reconsider where they throw those alarming red exclamation marks, since I keep hearing "it doesn't matter".

 

[ajw22]

Well, yeah... I know 7.1 ain't bad. But that big red exclamation mark staring at me from the PoolMath Overview page just won't leave me alone, so I must drive it toward middle of range. Human nature.

Are you going to let your life be driven by robots?

You have free will.

I'm bummed that adding stabilizer didn't even nudge my TA a little, I think it's just destined to be forever high.

Stabilizer does not lower TA. Adding Muriatic acid does.

I'm not sure how much that really matters, but again, those Darn red exclamation marks shout at me from the PoolMath overview page.

Psychologists could learn a lot from studying human reaction to PoolMath. Or conversely, the developers of PoolMath might want to reconsider where they throw those alarming red exclamation marks, since I keep hearing "it doesn't matter".

The exclamation marks get your attention, get you thinking, and focused on certain areas of concern.

You have the judgement to determine the correct action, not PoolMath.

 

[P00LNerd]

Are you going to let your life be driven by robots? ...You have the judgement to determine the correct action, not PoolMath.

You are apparently not familiar with my particular flavor of OCD.

 

[Newdude]

Go into settings, then advanced settings and turn off 'ideal level'. Poolmath doesnt know understand the date, the climate, the fill water, the weather, or what you've found works best with your unique pool.

Any 7.X Ph is equally fine.

 

[P00LNerd]

Poolmath doesnt know understand the date, the climate, the fill water, the weather, or what you've found works best with your unique pool.

Here's the trouble: neither do I!

"Follow your experience" doesn't work well for those lacking it, following the hopefully-well thought advice of whoever coded that app is surely safer for most, than ignoring them.

 

[Newdude]

Here's the trouble: neither do I!

Thats why you have us.

Come ask anytime and we'll fine tune your plan. Or help hatch it in the first place.

Id leave the 110 TA alone and lower Ph at 8+. The TA will come down and settle where it wants to be.

 

[P00LNerd]

Hah, just checked back in and saw this. With the cover off, the pH has been skipping up nicely, 0.2 - 0.3 ppm per day. I've been adding 12 oz. of 35% muriatic each day, knocking it down to 7.2 so it can climb back to 7.4 the next day. I expect this will reduce TA at a rate of 3 ppm/day, until I'm in range.

I know the high TA isn't bad for the vinyl, but the pool is surrounded by concrete bullnose and decorative concrete, which get splashed all day long. So the warnings about high TA causing trouble for concrete had me thinking it's not a bad thing to bring it inline with recommended range.

 

[PoolStored]

So the warnings about high TA causing trouble for concrete had me thinking it's not a bad thing to bring it inline with recommended range.

Who's warnings? TA will not hurt concrete.

 

[P00LNerd]

Who's warnings? TA will not hurt concrete.

PoolMath's warnings. The app is stating my CSI is lower than target range, with a warning that "corrosion is likely for stone and pebble pools". I know that TA and several other factors (pH, CH, temperature, etc.) all combine to drive CSI, but PoolMath offers no guidelines on how to correct a bad CSI.

So, because my TA is the only parameter that isn't already well-centered in the ideal range, I figured I'd at least nudge that enough to get the app to stop throwing warnings at me about that parameter. Once all parameters were in their target ranges, I figured it'd be easier to then evaluate and finally correct for CSI.

But what's weird is that my CSI is too low, it's at -0.8 whereas recommended is -0.6 to 0.6. I'd have thought that lowering my TA would drag CSI even lower, yet that's what the app is stating I need to do.

Anticipating your answer: If the app is wrong, seemingly nearly all of the time, why is it promoted as the best tool for TFP? It shouldn't be so code these conditions into the app, such as ignoring TA if it really doesn't matter for your pool type.

 

[Newdude]

why is it promoted as the best tool for TFP?

No matter what it says, it wont apply to many people, while still applying to most.

If it was up to me, it would say nothing at all, and only be a calculator.

 

[ajw22]

Low CSI does not matter for vinyl liner pools.

Only very high CSI may cause scaling on a liner pools.

If you keep your pH in the 7's you can turn CSI tracking off and ignore CSI.

 

[PoolStored]

Turn off CSI tracking.

Even if you got your temp up to 80, raised your pH to 7.8, lowered your TA to 80, you would still be -.59. If you further added enough CH to get to 200, you would still be -.37.

You are chasing something that isn't a something.

 

[P00LNerd]

Thanks, guys! I appreciate that. CSI tracking turned off!

You've probably noticed that putting numbers in front of me is like waving a bone in front of a dog... I'm going to chase them!

Is the high TA any concern at all? Scaling?

 

[ajw22]

Is the high TA any concern at all? Scaling?

No.