Tackle pH or TA first??

[stickerdude]

I have a new 27' x 52" above ground pool that's been full for 3 days. Am using a SWG and salt test this morning was 3200 ppm. Am getting free chlorine reading at 1 (am still running SWG around clock to get levels up). CYA was 30 and added 4 lbs more this morning. My real question: pH is at 8.2 and TA is at 270...The pool school recommendations are a TA of 60-90 and I know the pH should be no more that 7.8...sooo...which do I tackle lowering first and what's the best method? oh, yeah, I also have one of those return outlet fountains running all the time too which should theoretically help lower pH thru aeration right? That doesn't seem to be working as pH 3 days ago was 7.5.

Would appreciate some professional help!

Thanks!

 

[Richard320]

pH first. It's critical for eye comfort and to prevent scaling.

Use the pool calculator to determine how much acid you need to lower pH to about 7.2. Then plug that quantity in near the bottom where it shows the effects of adding chemicals. You'll see it will have a minimal effect on TA. Aeration will bring pH back up. More acid will lower pH and TA. And then pH will climb again. You can force the issue by vigorous aeration and maintaining pH or just let TA come down on its own. Either way will use the same amount of acid - it just depends on how fast you want it to happen.

But always maintain pH.

 

[PoolGuyNJ]

Turn off the cell so it doesn't scale up. Use bleach to bring/keep the FC level where it belongs.

Add acid to reduce both the pH and alk. Use the pool calculator to determine the amount of acid. Reducing the alk will be 1st. The pH will come down as a result.

Point the return up some to break the surface. This will help reduce the TA and raise the pH.

When you get back within normal, turn the cell on and use bleach as your FC elevation method.

Scott

PS Rich is fast today.

 

[dmanb2b]

Welcome to TFP

FC should be raised with liquid chlorine, not your SWG. A SWG is for FC maintenance and the is no need to strain the SWG to try to raise FC. Aeration raises PH (not lowers) without raising TA. Muratic Acid lowers PH and TA. Since you will be using a SWG, I would in this case begin the lowering TA process described below. I had a similar situation (TA @300+) and ended up using about 8 gallons over 3 days in a 24' pool.

pool-school/lowering%20total%20alkalinity

PS...I'm SLOW :lol:

 

[Richard320]

Turn off the cell so it doesn't scale up. Use bleach to bring/keep the FC level where it belongs.

Add acid to reduce both the pH and alk. Use the pool calculator to determine the amount of acid. Reducing the alk will be 1st. The pH will come down as a result.

Point the return up some to break the surface. This will help reduce the TA and raise the pH.

When you get back within normal, turn the cell on and use bleach as your FC elevation method.

Scott

PS Rich is fast today.

You sure you didn't get that backwards? Enough acid to drop that TA in one shot will dissolve the heater!

 

[loop_pea]

You need to bring down the pH first. TA does not really matter in the short term except that it tends to make pH rise. Aeration raises, not lowers, pH so that will contributing to the pH rise.

Your pH could actually be higher than 8.2 since a lot of tests can't read any higher than this, so it might take quite a bit of effort to get the pH down.

When you add acid to bring down the pH, the TA will also be reduced a little at the same time. If you keep your pH in range, then over time, the TA will come down to where you want it to be. Aeration willl accelerate this process, and you're already doing that.

There's a pool school article written by the experts here: http://www.troublefreepool.com/pool-school/lowering total alkalinity

PS I'm even slower!

 

[stickerdude]

ok, let me be sure I've got this clear...should I add the ENTIRE amount of acid ALL AT ONCE recommended by the pool calculator to attempt to lower the pH down to 7.2? Also: 1. pour it in thru the skimmer? 2. how long after adding is it OK to swim? 3. test and add more acid if needed again in 24 hours or sooner or longer?

I'll turn off the SWG until I get the pH and TA numbers right and use bleach in the meantime. Any harm in using shock if I don't have liquid?

Thanks for all the help!

 

[Bama Rambler]

Concentrate on the pH. The acid you add to lower the ph will lower the TA.
Don't add the entire amount the PC says to the first time. Add about 75% of that amount and give it 30 minutes and retest. Then add again.
1: DO NOT pour the acid in the skimmer!! Pour it in front of a running return. A slow steady stream is the best way.
2: Once you have the pH down between 7.2 & 7.8 give it 30 minutes to circulate and go swimming!
3: Once you have it down in the 7's you can test it a couple of times a day with a TA as high as your's.

Once you get the pH down you can actively lower the TA by lowering the pH to about 7.0 and aerating to bring it up again. To lower TA you're actually playing with the pH and the side effect of that is that the acid lowers the TA too.

 

[aa62579]

Make sure you plug your TA into the pool calculator to get the right MA amount. Some people only concentrate on the pH box. The higher TA will require more MA to drop the pH.

 

[aa62579]

Also, don't get discouraged if that first dose does not lower your pH enough. I found when my TA was high that the suggested amount of MA was never enough. The farther away you get from ideal numbers, the bigger the margin of error is. Go ahead and be conservative at first if you like, but just be prepared that it might not drop the pH as much as you had hoped. Don't get discouraged, just plug the numbers back in and add some more.

 

[stickerdude]

thanks again! I had already added some MA and had decided that sending thru the skimmer seemed like a bad idea! so I did pour it in front of the return. Also good to know I don't need to wait so long between MA applications. I think I plugged in the TA to the calculator but that's good advice, too, and I'll be sure to do that as I retest and re-treat.