TA too high: To lower or not to lower

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D

davida7

0
Mar 31, 2011
8
SE Oklahoma
Hello all,
New to TFP and I have LOVED the great information in the Pool School. There are two pieces of advice that seem to be in conflict and I just want to do the right thing. I have a SWG so I'm following the info in the section related to Balancing a Salt Water pool. In it, it says the TA should be between 60 and 90 and then it says "THIS IS IMPORTANT!" Well, my TA is 180--way too high, so I went to see how to lower it and it says "You shouldn't lower TA just to reach a target number. Make sure you actually have one of the above issues before lowering your TA." Well, I don't have either of those issues. My plan is to not worry about it, but I just want to be sure. The "THIS IS IMPORTANT!" has me a little worried.

For the record, my water looks fantastic--best yet! :party: (Put the pool in last summer and got to swim Aug-Oct. Can't wait to get in this year!)

FC=1.5 (See CYA below)
CC=0
pH=7.8
TA=180
CH=120
CYA=0 (I just added Stabilizer and it's climbing. My SWG was set to 100% and still barely getting a FC reading. I learned from Pool School that I needed to add Stabilizer. It's working out and I'm working on getting CYA in the 70-90 range per Pool School.)
 
Sportsman said:
does your pH creep up? You're at 7.8, the top of the range. MY fill water is high TA and my pH creeps up steadily. I've not tried to aggressively lower TA by acid and aeration but it is slowly coming down by adding once a week to keep pH in check.
Click to expand...

I guess it does creep up. I'm still new at this so I don't really know trends yet, but yes, my pH is a little high. What do you add once a week to bring it down? Just M acid?
 
I think you should just lower your TA in STEPS---not all at one time. Do it over the course of a couple of weeks. Easier to keep your ph in range if your TA is not totally out of whack. Get your FC in range to where you "think" you've raised your CYA level to. Don't wait.
 
Right now, your calcium level and the water temperature are low enough that you're not at too much risk of scaling in the cell. However, as the water warms up, your risk of scaling the cell goes up quite a bit.

You should get your TA down to about 80 and you should raise your Cyanuric acid to about 60 to 80 ppm. Maintain your pH at 7.3 by adding acid as necessary and this will cause your TA to steadily decline.

Once your TA gets down to 80, then you can begin to maintain your pH at about 7.6.

What is your current water temperature and how high will it get at its highest?
 
davida7 said:
Sportsman said:
does your pH creep up? You're at 7.8, the top of the range. MY fill water is high TA and my pH creeps up steadily. I've not tried to aggressively lower TA by acid and aeration but it is slowly coming down by adding once a week to keep pH in check.
Click to expand...

I guess it does creep up. I'm still new at this so I don't really know trends yet, but yes, my pH is a little high. What do you add once a week to bring it down? Just M acid?
Click to expand...


Use the pool calculator to determine how much muriatic acid you need. When my pH gets to 7.8 I drop it to 7.2. At first I was adding acid every 5-7 days. I was probably at 7-10 days by the end of summer. I didn't creep up over winter but now that I'm running pump again I guess I enough aeration that pH is rising again.
 
Here's the sticky on lowering your TA.

pool-school/lowering%20total%20alkalinity

Basically, the process of lowering your TA is simply by acid additions, followed by aeration. You add enough acid to lower the pH to 7.2, aerate the pool water to cause the pH to rise back up towards 7.8, and then repeating the process until you aachieve your desired TA. A TA somwhere around 60 to 70 is about perfect typically. Any lower than that and your pH can tend to fluctuate wildly following chemical additions.

It's important to understand that it is acid that lowers the TA. Lowering it is also a process that can take several weeks. You can raise TA quite quickly but lowering requires patience and persistence.
 
Thanks everyone. Your advice is very consistent with all that i've read through Pool School here on TFP. The thing that I'm still not clear on is the fact that the Lower Alk page says NOT to lower your Alkalinity if you don't have one of those two problems. Since I don't have one of those two problems I'm inclined to leave things alone with regards to TA
 

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It's going to take A LOT of acid in a 26k gal pool to lower TA from 180 to the 60-80 range. If you just focus on making sure PH never goes above 7.8, your TA will come down on it's own, via frequent acid additions. At 180, with a SWG, it won't be long until your PH will want to rise. That said, if it's locked in at 7.8 and your CH remains low, just keep an eye on it.
 
I'm assuming that your current water temperature is low now, right? As the water warms up, the CSI will increase and the carbon dioxide will begin to off gas much more quickly, which will cause the pH to rise much faster and it will increase the risk of scaling in the cell. By beginning the TA lowering process now, you will prevent problems that could be caused by the warmer water.

Based on your current numbers, your CSI will turn positive at about 75 oF

I recommend that you keep you CSI in the -0.4 to -0.1 range. I recommend that you lower the TA to at least 120. Lowering the TA by 60 ppm in 26,000 gallons will take about 3 gallons of acid (cumulative total added in small amounts over time, not all at once).
 
dmanb2b said:
...If you just focus on making sure PH never goes above 7.8, your TA will come down on it's own, via frequent acid additions.
Click to expand...

That's how it worked for me. My TA just kind of found its happy place after knocking the pH down repeatedly to keep it below 7.8.
 
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