Borax addition increased TA 60ppm after pH balanced

[DanielP]

Is it normal for TA to increase after you've increased your Borates from 0ppm to 49ppm (13 boxes (988 oz) in 17,100 gallons pool) and then add enough muriatic acid (4 gallons) to bring pH back to 7.5? I started with 140ppm TA and now it is 200ppm.

Using pool math, I thought that the TA was going to rise 113ppm from adding 13 boxes of 20 Mule Team Borax and decrease 117ppm from adding 512 ounces of 31% muriatic acid.

If the TA increase is abnormal, do you guys think that adding the Borax in the skimmer "cleaned" my sand which released TA that was somehow clinging to my sand? I have had scaling a few years back that may have affected my sand in the past, but it's been cleaning well. I didn't add acid through the skimmer, I added one gallon in front of the return jet after every 3 boxes of Borax through the skimmer.

The water feels "sticky" when I rub my fingers together now while it didn't in the past. I verified this is a side effect of high TA.

I know I need to add muriatic acid and aerate, I just wondered if others had this problem before.

 

[astrong]

I just went through this. Lowering my TA. Did you read the "add borates thread"?
You needed to get your TA to 70-80 ppm and pH around 7.4-7.6 before adding borates.
Did you add half acid first? Then half borax? Brush? Then add rest of acid? Rest of borax? Brush? In that order????? With pump running????

I went in that order with TA at 80 to start and pH at 7.4
After adding everything in the order I described I'm at 90 TA and 7.6 pH so far.

I'm not sure what to recommend but I'm sure someone will chime in.

 

[DanielP]

No, I didn't read a how to thread I just used Pool Math. I've now looked at two posts: 1) The current sticky in Chemistry 201 - Borates - Why and How; 2) So you want to add borates to your pool--Why and How

In thread 1 it says to adjust the TA to the lower end before starting because it will be easier to adjust. It says to add acid first but not why, I assume it is to prevent really high pH that can cause scaling, not sure. It does say I can add the Borax to the skimmer and to pour the acid in front of the return jet, which I did. It says to brush if there is any undissolved Borax, but I don't have any.

In thread 2 it says to adjust TA to my target level first, then adjust pH to 7.4-7.6, then add half the total acid, then half the total borax, then brush and repeat acid/borax/brush. I did not brush because there was nothing to brush.

My process went like this with no waiting or brushing:
3 - 76oz boxes of Borax in skimmer
1 - 128oz jug of 31.45% Muriatic Acid in front of return jet
3 - 76oz boxes of Borax in skimmer
1 - 128oz jug of 31.45% Muriatic Acid in front of return jet
3 - 76oz boxes of Borax in skimmer
1 - 128oz jug of 31.45% Muriatic Acid in front of return jet
3 - 76oz boxes of Borax in skimmer
1 - 128oz jug of 31.45% Muriatic Acid in front of return jet
1 - 76oz box of Borax in skimmer

I measured pH 30 minutes after the process was done and got 7.5 pH. Two hours after the process, I felt the water and it was sticky feeling between my fingers. I tested pH again and it was 7.5. Then I tested TA and it measured 200. For my specific problem, if borax wasn't mixed well, TA should be lower than expected, not 60ppm higher. If the Acid didn't mix well, the pH would be much higher than it is now, and I've never had an issue with muriatic acid mixing and showing up on a test as expected within 30 minutes when I add it in front of the return jet. Based on the above expectations regarding mixing and the current sticky only recommending brushing if you see Borax which I don't, I don't see a reason to brush.

I started aerating and ran to Lowes after posting and bought 4 gallons of muriatic acid because Ace was closed. Unfortunately I grabbed 14.5% on accident so I'm going to have to purchase more. I've added 2 gallons of 14.5% so far and am waiting on aeration to restore pH.

What I really want to know is if it's normal for TA to increase 60ppm, and if not, what may have caused it. I certainly didn't expect this going off what PoolMath showed.

- - - Updated - - -

The only additional thing I can think of that might help someone is there may have still been some undissolved CYA in my sand filter when I added Borax in the skimmer.

 

[astrong]

I'm no expert but I read and read for weeks about adding borates.
It was very important to have a TA of 70-80 to start and that's a maintained stable level.
Secondly. Borax increases pH and TA. Muriatic acid lowers both pH and TA. Putting in the acid first to me is like a buffer to prep you for the borax. MA goes in first in front of return with pool on.

Borax is fine to go in skimmer. I added little by little and watched as it went through pump as to not clog. (Just in case)
Brushing may not be to brush anything other than stir up water because the acid is heavy and sinks. Brushing pool stirs the water so acid and borax are not gathering or pooling in areas.
Doing it in Doses in between brushing stirring helps acid and borax mix.

My best guess (experts please give your input) is you added borax first. TA was already high. Borax raises TA and ph.
Lowering pH with MA happens pretty quick so getting a stable pH is easier than controlling TA trust me.
See what the pros say but that's my thoughts.
Really read about borates, alkalinity and pH. Now that borates are in TA is much more difficult to lower but it can be done. Watch your ph during this process. Ph drops at a much faster rate than TA.

 

[DanielP]

I didn't think to follow a tutorial because PoolMath says what to do and in what order to do it, and it's exactly what I did except I took did it in smaller increments instead of all the Borax and then all of the MA.

Looking back over the tutorials nothing warned of a 43% spike in TA if it's not down to 70-80 before the process is started or that something bad will happen if you add the Borax before MA. The tutorials do say to balance TA first because it's harder to adjust later. PoolMath led me to believe that effects of adding 13 boxes of Borax and 4 gallons of 31% MA would decrease the TA instead of increase, it only warns that large changes to pH are uncertain. My spike is also 3.42 times the 12.5% spike (from 80 to 90) you had.

Anyways, thanks for trying to help, I just don't see a clear explanation for my problem in the tutorials that would explain why PoolMath's "Effects of Adding Chemicals" is wrong about the amount TA changed from the Borax and MA. Hopefully an expert will be able to explain it.