Bringing down TA / balancing pH

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Lonnybass

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Jun 26, 2018
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San Diego
Greetings all-

I am continuing to rebalance my pool after doing a citric acid treatment last month. Generally speaking, things are balanced out and in good shape. However, I'm struggling to bring down my TA level to where it needs to be. Here are my latest test results:

Free chlorine 7.0
Combined chlorine 0.0
pH 7.4
TA 170
CYA 30

Please let me know your thoughts. I have been adding muriatic acid steadily to maintain our pH level, but I can't get the TA to budge below about 150.

Thanks everyone!

Lon
 
The current pump settings have the waterfall running at full strength in the morning for about an hour, and again for two hours in the early evening.

During the day while the solar system is activated, it's a steady trickle, enough to gently break up the surface.

Should I crank it up for a more powerful flow during the day and overnight hours?
 
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The key to lowering TA seems to be keeping a fairly low pH while doing the aerating. I find that it works best in the 7.0-7.5 pH range. I lower the pH to around 6.8-7.0, then aerate while monitoring pH rise. As soon as it starts rising, at or before it gets to 7.4, I knock it back down to around 7 again. Most of the change in TA happens when the pH is in the lower region. Many fail at lowering TA because they are trying to do it by aerating with pH in too high range (7.5-7.8).

It seems that pH rises, and TA falls quickest, when pH is low.
 
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chiefwej said:
The key to lowering TA seems to be keeping a fairly low pH while doing the aerating. I find that it works best in the 6.8-7.5 pH range. I lower the pH to around 6.8-7.0, then aerate while monitoring pH rise. As soon as it starts rising, at or before it gets to 7.4, I knock it back down to around 7 again. Most of the change in TA happens when the pH is in the lower region. Many fail at lowering TA because they are trying to do it by aerating with pH in too high range (7.5-7.8).

It seems that pH rises, and TA falls quickest, when pH is low.
Click to expand...

Thanks! I'll try lowering into the next tier.
 
chiefwej said:
The key to lowering TA seems to be keeping a fairly low pH while doing the aerating. I find that it works best in the 6.8-7.5 pH range. I lower the pH to around 6.8-7.0, then aerate while monitoring pH rise. As soon as it starts rising, at or before it gets to 7.4, I knock it back down to around 7 again. Most of the change in TA happens when the pH is in the lower region. Many fail at lowering TA because they are trying to do it by aerating with pH in too high range (7.5-7.8).

It seems that pH rises, and TA falls quickest, when pH is low.
Click to expand...

That's what has worked best for me - getting the pH very low and immediately aerating. I've also found that lowering TA takes more than a few days. Patience is required.
 
Can you run your spa without the heater? I have found that running my spa jets 24/7 for aeration works well for my pool. It still takes patience and careful monitoring (and a fair amount of MA) to lower TA.
 

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chiefwej said:
Can you run your spa without the heater? I have found that running my spa jets 24/7 for aeration works well for my pool. It still takes patience and careful monitoring (and a fair amount of MA) to lower TA.
Click to expand...

I can indeed run it without the heater, but since it all runs off one pump I'd need to switch the direction of the spa valve to push the pool return through the spa lines. I'll give this a shot right now to try and get some more movement than just the waterfall spillover.
 
Looks like the 7.0 pH target and added aeration have already started making a difference. I just retested and TA is already down to 140 from the 170 result I got last night. I'll just keep holding the 7.0 target through the week to see how the numbers balance out.
 
Flying Tivo said:
Its not about holding PH at 7, let it rise to 8 by aeration then add acid to drop down again to 7. Thats how you get the best results
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I completely disagree. I never let the pH get above 7.5 while trying to lower TA. Keeping the pH low while aerating is the key to lowering TA. It’s in that lower pH range (7.0-7.6) that the aeration does its thing. Once you get the TA where you want it, then you can let the pH rise to your goal.
 
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My understanding was that the addition of acid lowerd the TA/PH and aeration raised the PH only. I rather handle one big dose than multiple smaller doses, but the effect might be in the same proportion. Maybe @chem geek can help us better understand the chemistry.
 
Felipe,
I suggest you read the article on lowering TA. It recommends a 7.0-7.6 range for lowering TA. and also states “Lowering the PH back to 7.0-7.2 more frequently will also speed up the process...”.

Living in Tucson with very high CH and high TA in my fill water, lowering total alkalinity is something I have to deal with on a frequent basis. It is clear that necessary off gassing takes place at the lower pH levels.
www.troublefreepool.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.
www.troublefreepool.com www.troublefreepool.com
 
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Lonnybass said:
Looks like the 7.0 pH target and added aeration have already started making a difference. I just retested and TA is already down to 140 from the 170 result I got last night. I'll just keep holding the 7.0 target through the week to see how the numbers balance out.
Click to expand...
When you say "holding" do you mean lowering it back to 7? :)

How are things going?
 
splashpad said:
When you say "holding" do you mean lowering it back to 7? :)

How are things going?
Click to expand...

Yep - lowering back down to maintain the 7.0 target. I checked last night and pH was still where it was supposed to be. This morning's test showed a rise to 7.4 so I dropped it back down again with muriatic acid.

TA is at 130 as of this morning's test, down from 170 on Sunday.
 
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chiefwej said:
Felipe,
I suggest you read the article on lowering TA. It recommends a 7.0-7.6 range for lowering TA. and also states “Lowering the PH back to 7.0-7.2 more frequently will also speed up the process...”.

Living in Tucson with very high CH and high TA in my fill water, lowering total alkalinity is something I have to deal with on a frequent basis. Perhaps I’m a bit overly aggressive with a 6.8-7.5 range, but it is clear that necessary off gassing takes place at lower pH.
Click to expand...

Adding the acid is what brings down the TA. If you do several dosing from 7.5 to 6.8 or one large from 7.8 to 6.8, the amount of acid will be the same to bring the TA to the same level. I dont know if off gassing is better at lower/higher PH, but the amount/quality of aeration is what make the process go faster, not the adding of acid.

I also like to go down to 6.8 but did not want to mention it as to not confuse the New guys and whats posted.
 

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