Low pH and TA

[minisoda]

I’ve been trying to get my pH up for a couple years and it appears it came back to bite me. Acidity in the water appears to have destroyed the pool heater. TA is quite low as well and not sure how to handle that. Appreciate any recommendations!

Ph 6.6 or less (measured 6.2 on test strip)
FC 2
CC .5
TA 40
CH 500

I tried using air to increase the ph, but was never successful. Could try really pumping air in with a large air compressor as a next step.

 

[mknauss]

How are you testing your water chemistry? Strips do not count.
What is your CYA?
How do you chlorinate?
Raise your TA to 70 ppm.

 

[minisoda]

Using a kit I purchased here for testing. Ph is below the reading of my kit but the strip does register it at 6.2.

CYA 40.
Just opened the pool and was planning to use cal hypo.

 

[mknauss]

OK -- best to use baking soda first to see if that resolves the situation. Raise the TA to 70 ppm and circulate well. Test pH and TA. If pH still below 7, use Borax to raise the pH a few points.

Cal Hypo will also raise your pH some. Be sure it does not sit on the pool surface as it will stain it.

 

[minisoda]

Thank you, sir.
12 pounds of baking soda 12 hours ago barely touched it. Added another 12 this morning and will test again this afternoon.

 

[mknauss]

The baking soda did not raise your TA?

 

[minisoda]

Yes, TA is about 100 so I need to be very cautious on the baking soda now. Starting to see the pH come up as well.

 

[IceShadow]

Aerate to increase pH at this point.

 

[minisoda]

Man, I tried everything short of an air compressor to bring ph up a couple years ago and it did nothing. Do I need to just setup a large compressor and let it go for a while???

 

[mknauss]

You have to leave the cover off the pool, at least during the day. Wind causes aeration. The CO2 also can off gas when the cover is open.

 

[jseyfert3]

Washing soda will raise pH (along with adding TA).

What is the pH now?

 

[minisoda]

pH currently measuring 6.8. I’m going to give it another go with the air compressor and ensure we leave the cover off during the day.

 

[minisoda]

60 psi pumping into the water! Pretty sweet! Now just need to see if it brings up the pH.

 

[minisoda]

So the air compressor for a couple of hours had zero affect on the ph and I didn't want to run my nice expensive air compressor for days on end.

Dumped in 16 pounds of Borax this morning (per pool math) and voila! Sitting right at 7.5.

Unfortunately the water really clouded up after the Borax... hopefully the filter clears that out in the next couple days!

 

[mknauss]

Because your TA is high, the borax caused carbonate to precipitate. It will redissolve slowly.

Your TA number cannot be as high as you say and have no pH rise. Chemistry demands it.

 

[minisoda]

Understood on the carbonate... good to know it will dissolve!

Not following your second point. Our pH did rise and is now right where I want it to be.

 

[mknauss]

The pH would rise naturally with a TA of 100. No borax needed. I suspect your TA is now higher.

 

[minisoda]

Ah, I understand! I'm a little gun-shy after the low pH destroyed our pool heater. Was working to get it up quickly. I will post new numbers shortly.

 

[mknauss]

Ah, I understand! I'm a little gun-shy after the low pH destroyed our pool heater. Was working to get it up quickly. I will post new numbers shortly.

Do you have a tablet chlorinator thing? Did you use it in the past? The use of trichlor, and especially leaving tablets in a chlorinator with the pump off, will destroy the heater.

 

[minisoda]

No. Used tricolor in the past until we had a CYA issue and had to drain/refill. Since then have done pure bleach and last year mostly cal hypo.

We've had the pool for 6 years and it's had low pH since day one... I just ignored it since the pool was crystal clear. Learned my lesson... from everyone I've talked to, low pH is the cause here.