What did I do wrong with my pH?

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C

CHD Dad

0
Jul 18, 2012
89
Upstate, SC
Hey everyone. New pool owner here. Still trying to figure out this testing and treatment!

I tested my water three days ago and I had
pH - 7.0
TA - 40

I punched that info with everything else into the Pool Calc and I got
Add - 183oz of Baking Soda for TA - to raise to 70
Add - 96oz of Borax for pH - raise it to 7.6

I didnt want to over shoot things so:
Two days ago I added 176oz (11 lbs) of Baking Soda. - PH is now between 60-70 (starts to clear up around 6 drops, 7 drops is almost too much). pH did not appear to change although I thought I read it would.

Yesterday I added in 76oz of 20 Mule Borax (1 box)
Today my pH is 8.0 or maybe higher. It is definitely 8.0 in my test kit. It appears to be 8.0 and not higher on a strip.

So I added 20oz less that what was called for by the Calc and overshot my pH by quite a bit.

Now the calc is telling me to add 5.6oz of liquid acid or 7.6 of dry acid to lower it back down to 7.8.

I really dont want to yo-yo back and forth on my pH. Am I doing something wrong? Can we still swim in the water with a 8.0pH? We had friends with kids coming over in a few hours to swim and I dont want anything to go wrong!
 
If you have some muriatic acid I would go ahead and dump some in before company comes to lower the pH a bit. About 26 oz would lower it from 8 to 7.5. Test after half an hour just in case your pH was well above 8 when you added. I'd worry about everything else after company leaves.
 
Something is throwing off your calculations. You might have entered an incorrect number for pool size, TA, or Borates in the calculator. PH changes are affected by all of those numbers. If you can't find what is going wrong with the calculation, you can do the adjustment yourself by using lower percentages of what the calculator is suggesting. It sounds like you should be adding less than half the amount of acid/base rather than 3/4.
 
I just looked at the calc again. Pool size is correct. I cant test for Borates with my test kit. I have the Leslies DPD Complete kit. I bought it before reading about the FAS-DPD. It is this kit - http://www.lesliespool.com/Home/Pool-Ch ... 81330.html. I just rechecked all the info entered in the calc and they all match what I just tested. I had my old values written down and reentered them and I got the same results as a few days ago.

I dont have any acid. I will get some right now and slowly add it in and test as the day goes on. The friends will be here in 4 hours.

BTW - any reason why the calc figured out the TA correctly but not the pH? I still want to raise the TA slightly but I didnt add in the full amount of baking soda.

I did just look at the calc again - I did not update the TA to the 70 level. It is telling me to add in 26oz of Acid to lower to 7.6.
 
TA calculations are simple math, take the change required and multiply by a constant. Calculating PH changes requires complex non-linear equations that depend on several different levels. Because PH changes depend on several different levels, each of the different testing errors when measuring those levels increase the error in the final result.
 
I had no errors in my original Calc entries. The only thing I could not enter a value for was Borates which I cant test for. All other values I could enter matches my test results both times I used it. It worked perfectly for bleach when I needed to raise my chlorine levels when I first used the pool. CYA was also accurate when I needed to add more to raise it. I just really overshot the Borax level somehow. I'll get the acid and see how it goes from here. I plan on only adding 1/2 the amount listed first, test in 45-60 minutes and go from there. I am off to the store now to get it!

Appreciate the help!
 
Update time. Added 24oz of liquid acid with my pump at medium high speed. Slowly added it right by one return port.

After 1-1/2 hrs my pH is now 7.6. Very happy! Now lets hope I can keep it there!

Still not sure what happened with the Borax but I am good now and I have plenty of Borax and Acid on hand should I need to tweak things.

Thanks again.
 
I think Jason meant you might have a figure entered in the borates field in the calculator, not that you need to measure your borates in the pool. If you had significant borates in the pool, it would have caused your pH to not swing enough, not too much. Just keep that number in the calculator at zero, and don't worry about measuring it.
 

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CHD Dad said:
Update time. Added 24oz of liquid acid with my pump at medium high speed. Slowly added it right by one return port.

After 1-1/2 hrs my pH is now 7.6. Very happy! Now lets hope I can keep it there!

Still not sure what happened with the Borax but I am good now and I have plenty of Borax and Acid on hand should I need to tweak things.

Thanks again.
Click to expand...
So....How does it look? Crystal clear? Does it have that sparkle all the borate users rave about?
 
Richard320 said:
So....How does it look? Crystal clear? Does it have that sparkle all the borate users rave about?
Click to expand...

Pool has almost always been crystal clear. I had one silt issue right after it was filled with water but after that it has been clear. My original chemistry was WAY off too! I had almost zero chlorine and all the other numbers were way off. Not sure about "sparkle" but it looks great to me! I plan to keep with the baking soda and borax. Cant beat the price and it seems to work great. Hopefully I dont need to worry about bleach since I have a SWG working well.
 
RobbieH said:
I think Jason meant you might have a figure entered in the borates field in the calculator, not that you need to measure your borates in the pool. If you had significant borates in the pool, it would have caused your pH to not swing enough, not too much. Just keep that number in the calculator at zero, and don't worry about measuring it.
Click to expand...

Borate field was zero. I will just go easy on the the amounts the next time and use the suggested amount as the max.
 
RobbieH said:
I'm surprised you had to RAISE your pH with an SWG in use.
Click to expand...

It hasnt been in use very long. I had it setup wrong from the start and needed bleach just to get some chlorine to show up on my test kit. The whole pool install was not a very smooth or easy process... The pool was just filled 7/3 and my SWG has only been in real use maybe a week and a half.
 

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