Is there a certain window of time

[Rangeball]

I'm also dealing with a high TA.

Are you also adding CYA? I think this will make it look like your TA and PH are going up when they are not.

Nope, only using bleach. CYA is about 20ish and holding.

Aerating actually causes your PH to go up. The only way Aerating will work is to keep adding Acid....if you can keep the PH low for a period of time then the TA WILL drop. It can take weeks.

Shoot for a constant PH of 7.0 (6.8 for a plaster pool) and watch your TA closely. When it starts to drop it will drop significantly.
Also remember that TA isnt a thing, its a measurement of the waters resistance to changing PH. It can go back up and in my experience will bounce around a little while you are trying to stabalize the PH.

I had to add 3" of water to make up for evaporative loss last night. Since my fill water is highly alkaline and lower PH than my pool, I waited until it was circulated and retested. PH was down, Alk was 190.

The Alk number doesn't bother me (vinyl liner), but the PH tends to shoot back up within days, so I'd like to get it down to 100 or so and see if my PH stays more stable. Water clarity and feel is much better when I keep the PH between 7.2-7.6 ish.

I set up my sump pump to aerate, but we have a good chance at thunderstorms today so I'm waiting to add acid and start aerating until I see what the rain does to the water. If it doesn't have much affect or misses us again, I plan to attack the alk daily until it drops to where I want it.

This is all from info I've gleamed out of this forum, I'm still working on it myself.

Thanks. I try to read as much as possible before asking questions, but this one has been stumping me. I'm starting to think it's primarily the high starting alk that is making it so hard to keep alk down permanently (ie, without adding fill water). Once alk is lowered and properly aerated, it shouldn't rise sharply, right?

[Tredge]

Higher Alkalinity means a more stable PH, lowering the TA means the PH will actually be less stable.

I have the same trouble you do with Fill water....it will always creep up when you have to replace from evaporation.....although slowly.

My plan is to get the TA down to somthing reasonable so that I can get a stable PH....then forget about the TA and Stop aerating.

Remeber that aerating will raise your PH. If you have a PH you like, then Stop aerating and dont worry too much about the Alkalinity.

Unless you have a problem with scaling I would forget about trying to "fix" the TA because your fill water will mean a constant battle....you'll never get it to stick at a low number.

No matter what you do you'll probably always have to add Acid....the good news is that your PH should stay fairly steady compared to other pools. The High TA doesnt cause the PH to shoot up....thats another problem and may be related to your TA increasing on you.

Once alk is lowered and properly aerated, it shouldn't rise sharply, right?

Thats my understanding from the technical explanations yes...but I have seen it bounce around a bit, I always attributed it to my testing or other factors.

[Rangeball]

Higher Alkalinity means a more stable PH, lowering the TA means the PH will actually be less stable.

That's what I understood. However when I get my PH down to 7.2, it's back up to over 8 within a week. Perhaps that's just part of the BBB method, and I should just be happy to acid each week to knock it back down?

I have the same trouble you do with Fill water....it will always creep up when you have to replace from evaporation.....although slowly.

Mine seems to shoot up as fast as the PH does.

My plan is to get the TA down to somthing reasonable so that I can get a stable PH....then forget about the TA and Stop aerating.

Mine too, but it's not working very well

Remeber that aerating will raise your PH. If you have a PH you like, then Stop aerating and dont worry too much about the Alkalinity.

When I do this, the PH continues to shoot up. It's hard to stop aerating when cannon balls are so much fun That's why I started this thread. It seems like just swimming and general splashing around is causing the PH to climb. Since the alk climbs with it, I figured I'm not doing a good enough job aerating, and the carbon dioxide formed from lowering the PH is being re-converted to whatever instead of gassing off, giving me the increased alkalinity reading.

Unless you have a problem with scaling I would forget about trying to "fix" the TA because your fill water will mean a constant battle....you'll never get it to stick at a low number.

My grand vision was to get the alk down, then as I have to add an inch or two of fill water, I can easily beat it back down. Do you think this is futile?

No matter what you do you'll probably always have to add Acid....the good news is that your PH should stay fairly steady compared to other pools. The High TA doesnt cause the PH to shoot up....thats another problem and may be related to your TA increasing on you.

If my PH would remain stable, I wouldn't give the alk a second thought. Whats the other problem you mention in your last sentence?

Thats my understanding from the technical explanations yes...but I have seen it bounce around a bit, I always attributed it to my testing or other factors.

I've tried to be as precise and consistent as possible in my testing, but it's possible I'm getting bad readings, I guess.

Thanks a bunch for the input

[Rangeball]

I forgot to add above-

Looks like the rain has a great chance of missing us again, so when I was home this noon I tested again.

PH- 7.8, up .2 from yesterday
Alk- 190

I added the acid to knock PH down to 7.0, and set up my sump pump with a hose returning to the pool to aerate. First time I've done it this way. I also plan to do some serious splashing about this evening

I'll retest in the am, and assuming alk has dropped, will knock ph back down and continue daily as needed.

[Tredge]

I'll be curious about your results in the morning.

The problem I was refering to about your PH climbing is an unknown....what I was trying to say is that a high TA doesnt cause the PH to rise, "somthing" else is causing them both to rise.

What that somthing else is....other than your water source...is still a mystery. Someone smarter than me will have to answer

[Rangeball]

I'll report back in the morning.

Looks like the rain may be re-grouping and we may get some after all. I won't hold my breath

From what I understood in the "lower your alk" sticky, if you don't gas of the C2O when the PH is down it can convert back and measurable alk goes back up with the PH.

I'm hoping that my previous aeration efforts were just inadequate. We'll see.

[Rangeball]

Got up early, grabbed my test kit and headed to the pool. It never did rain.

Pool had been aerating since noon yesterday.

Tested-

PH- 7.6, only dropped a bit.
Alk- 180, only dropped a bit.

I had expected a much bigger PH drop from the amount of acid I put in. I also expected the alk to be much lower.

I thought about this for awhile, and came up with a hypothesis.

In the "lower your alk" sticky thread, a poster asked if you could start aerating as soon as you add the acid. Ben responded stating it wouldn't work until the PH dropped but it probably wouldn't make a difference either way.

I'm wondering if thats correct.

If aeration increases PH while gassing off carbon dioxide to keep alk down, adding acid and immediately aerating seems counter-productive. My pool has been constantly aerated either by young swimmers or air in my return line. In looking back, the only time I got a good PH drop was when I had the air leak stopped and was getting good flow with no aeration and low swimming load.

I turned off the sump pump aeration, and added more acid, but didn't have enough to get PH as low as I need. I'll get more some time today, retest my PH and add more. I'll then try to hold the kids off from swimming tonight, retest tomorrow morning and hopefully begin aerating then.

Make any sense?

If this doesn't do it, I guess I'll be forced to live with high alkalinity and rapidly escalating PH levels