Newbie - sky high TA

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dayhiker

dayhiker

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Jun 6, 2008
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Pell City, AL
New pool, I've been using the pool place, test kit came in today and here I am.

We had lots of kids (12ish) in the pool weekend.

FC 1.5
CC 0.5
TA 360
CYA 30
pH 8.0

My pool is 26700 gal and SWG.

I'm going to run the SWG all day to get the FC up.

From the poolcalculator it says 233 oz or muriatic and 143 oz CYA. I added about 3 #'s of stabilizer when I finished the test and will add the rest (6# container) tonight. It sounds like I should add another 3#'s tomorrow afternoon too.

233 oz of muriatic is tons. What's the biggest dose I should add at once? I'm thinking add 24 oz or so at a time. I can add 24 tonight, 24 before bed, recheck in the morning, do 24 then, and again in the evening and just repleat and retest until I get it and TA to where it needs to be. The 233 oz is based on getting the pH down to 7.2 so that the TA can get pulled down. I checked TA 2x to be sure I had the answser correct. Does this sound reasonable?
 
Are you adding the CYA because you want a higher CYA ppm or because you want it to lower your PH?


Stabilizer is only added to hit your target CYA ppm, to protect your FC from UV breakdown, NOT to lower PH.

If you don't want a higher CYA ppm, DON'T ADD the rest of your stabilizer tonight.

The PH drop from adding the acid is pretty quick, once the water is mixed. I've had good luck adding all I've needed at once, in front of the return, slowly so it has time to dilute and disperse quickly. But, I've never needed the levels you calculated.

It won't hurt a thing to add half, wait an hour or so, retest for PH then add whatever else is necessary. But if you feel comfortable that the acid amount is correct (never hurts to double check that your inputs where correct), as long as you pour the acid in slowly, in front of a return, you should be fine. I've always added the exact amount the calculator tells me, and always hit my target PH on the nose.

Once PH is lowered, don't forget to aerate. Adding the acid will lower PH and TA. Aerating will increase PH but not TA. Then when your PH is high again, you repeat the process, until your TA is where you want it.

One other thing, since you've added some CYA already, you'll need to retest for it in a week to get your new ppm then adjust your FC needs based on the new level.
 
Just caught that you are running a SWG, so you probably are striving to get the CYA up. It doesn't hurt a thing to add all you need at once, just remember that it takes up to a week to fully dissolve so don't backwash or add more until you are certain you are getting an accurate reading.
 
Your TA is very very high which is why it takes so much acid to lower the PH. The high TA level is actually why the PH got so high in the first place. You should lower your TA level, see this article for instructions on lowering TA.

PH calculations are always estimates, the real chemistry is complex. I would add one gallon of acid, give it an hour with the pump running and then test again and see where you are.

The CYA calculation is more accurate, but because it is so difficult to lower CYA if you accidentally get it too high, it is best to use perhaps 2/3rds of the total amount the Pool Calculator recommends, give it a week, and then test again and see where you are.
 
I would add enough acid bring the PH down to 7.0. Using your numbers that should be about 348 oz. This will at the same time lower your TA by ~50ppm.

Then aerate until it goes back up, add enough acid to bring ph back to 7.0, rinse and repeat.

It is fastest if you keep the ph close to 7.0, so I add acid when my ph raises back to 7.2.

Typically you should add half the required CYA, wait a week, then add the additional. It takes ~ one week for it to completely dissolve and you really don't want to go over.
 
So just dump a gallon in, wow. My return is on the bottom of the deep end. I should just slowly pour it in while talking back and forth along the deep end and maybe a bit around the corners, avoiding ladders and the like, correct?

On the CYA, I'll add a pound or two tonight and wait a week.


If a gallon lowers it 50 ppm and I'm at 360 and I want it around 80 then I have 5 or so cycles of this. Fun, fun.
 
When you do add the MA do it in front of a return jet, and slowly, you don't want it sinking to the bottom of your pool.

I would suggest adding more MA when the PH hits ~7.2. This lets you out gas faster, and reduces the amount of MA you have to add at any single dosing.

If you have a spa on your pool turn the jets on. Makes a huge difference.
 

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Here are my results from the pool store on 5/31.

TA - 137
pH - 8.1
CYA - 10

I've been adding acid to try and drop the pH but it hasn't budged over the last week. What could cause the TA to increase when I haven't added anything other than acid? Could their reading be bad which explains why my pH hasn't moved. I've probably added a half a gallon or so in the last week.
 
lovingHDTV said:
Do you know the TA of your fill water?

Mine is 220 so I'm always lowering my TA.
Click to expand...

Bingo, we have a winner. I did add about 2" of water last week. The water in my town has a very high mineral content. I had totally forgotten about that. Let's see, 2"*18'36' = 108 ft^3 = about 800 gallons.

When I did my testing, I got a cup from the cupboard, rinsed it really well with pool water and then brought a cup full in for testing. Since the test kit was new, I rinsed everything I used with pool water before use. I then rinsed with tap and then with pool water before air drying.
 
I added 1 gal of MA. 2 hrs later the pH is 7-7.2. I put on the deck jets and after 2.5 hrs retested.

FC - 2.0
CC - 0.0
TA - 260
pH - 7.2

I'm going to leave the jets on overnight. Hopefully, the pH will be back up so I can cycle back again to get that TA under 175 or so. Maybe the third cycle will get it where it needs to be.

Thanks for your help everyone.
 
I am also working on getting my TA lowered.. I am surprised by the recommendation to add an entire gallon at once. Not saying that is wrong.. but I thought I read somewhere on TFP to only a few cups at a time?
 
Nice upgrade.

As of Wed night:

TC 3
CC 0
TA 230
pH 7.4

We swam for an hour and had a good bit of eye irritation. Why? Those numbers look pretty good except the TA.


2nd question, what's the harm of higher TA assuming a vinyl liner? I know it takes more acid or baking soda to move the pH with the high alkalinity but it also takes lots of acid to just bring the TA down. The total amount of chemicals is probaby a push. Just curious.

Thanks for any insight into the two questions.
 

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