Lowering Total Alkalinity Without A Ph Change

[ronwell]

The method explained in this video claims that TA can be lowered without a significant change in Ph by stilling the water, pouring MA in deep end and then waiting 5-6 hours to begin circulating.

What do the experts here think?

 

[Donldson]

Here is some quick info and a link about the "acid slug" myth from this thread: Certified Pool Operator (CPO) training -- What is not taught

Procedures for Lowering TA
There is also the acid column or slug method myth that was discredited in this paper. It's not that the method doesn't work at all, since the amount of TA lowering is solely dependent on the amount of acid you add and not how you add it, but rather that it is not the safest method (pooling acid in one area can damage plaster/vinyl surfaces) nor the most efficient (it can take longer for the pH to recover in time for you to add more acid to lower the TA some more). The efficient procedure for lowering TA (especially lowering the TA a lot) is described in this post and in the Pool School Lower Total Alkalinity procedure. The procedure works because the outgassing of carbon dioxide is accelerated at lower pH as shown in this chart.

The handbook only says to add acid to lower the TA and does not discuss more efficient ways of lowering it via lowering the pH and increasing aeration (along with the acid addition).

 

[Richard320]

I think you're begging for etched plaster where the acid settles.

Acid column myth

 

[ronwell]

Cool. Now I know what the myth is called. I have a vinyl liner, not plaster, but I don't want that much acid sitting on anything I own.

 

[duraleigh]

Lower TA by following the procedures in Pool School. We've published that method for 8 years or more and it works!

 

[ronwell]

I'm in that process right now. I think going to build an aerator from pvc to go on a return. Like this one.

Should I expect this to be faster at raising Ph than pointing the eye-balls up?

 

[RobbieH]

The more aeration, the faster the pH drop. So an aerator will raise pH (and lower TA) faster than upward facing eyeballs. Or at least that's true on my pool as my eyeballs only cause a minor agitation when pointed up.

 

[ronwell]

@RobbieH I'm confused. I just added MA to lower Ph and TA. I want to raise Ph. I thought aerating is the only way to raise Ph without affecting TA. Did you mean raise?

 

[RobbieH]

My apologies, I will correct my post. Aeration will RAISE pH and lower TA. I was thinking about something else and typed the wrong thing.

 

[ronwell]

No problem. I just wanted to check my own understanding.

When I point my returns up I get serious agitation of the water. I have good return pressure and the eyeballs are not to deep in the water.

I will experiment with both methods and post findings, w/ some video.

 

[pooldv]

Yep, you've got it right. Acid to lower PH and TA and aeration to raise PH and not TA. The more aeration the faster the rise.

 

[ronwell]

PVC Pool Aerator - YouTube

Added MA, measured TA decrease, and trying to get Ph back up (so I can do it again). Ph is 7.2 before beginning aeration. I'll check Ph again tomorrow.

 

[JamesW]

Note that most of the original people who advocated for the slug method have realized that they were wrong.

 

[ronwell]

2-3 days of aerating (see my youtube video in my previous post) 8 hours each day brought my Ph from around 7 to 7.5 in my 22k gal. pool.

I wanted to include this info for anyone considering the acid slug (information on the web still advocates the acid slug method).

A little $ to build some kind of aeration apparatus and some patience and your Ph can be increased this way (and TA can be lowered gradually).