pH Under 7 After Clean Up

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
We are in the final stages of a pool remodel from heck and today the subcontractor that installed the stonescapes interior used a lot of MA as part of their second pass at a clean up. The pool has had water in it for a little over 2 weeks and we’ve been keeping it between 7.2-7.6. We noticed the tarnish being removed from our copper scupper and the PH is definitely below 7, maybe as low as 6. Is this going to cause problems for us long term?
 

JamesW

TFP Expert
Mar 2, 2011
27,697
When the ta is red, the ta is 0 or negative and the pH is 4.5 or lower, which is very dangerous to the copper in the heater and scupper style fountains.

To calculate the actual ta, use r-0006 base demand to titrate from red to green and then multiply the result by 6.3 to see how negative the ta is.
 

JamesW

TFP Expert
Mar 2, 2011
27,697
I would not leave the pH that low with the water going through the heater and scuppers.

I would bring the TA up to 80 and then recheck the pH the next day.

It's likely that a significant amount of copper has been stripped from anything that is copper.

You probably have a lot of copper in the water and you should be careful not to make it drop out as stains.

Don't use sodium carbonate or calcium hypochlorite as they can react with the copper and create stains.

What is the builder supposed to be doing with the chemistry?
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
The builder is useless. The interior installer seems like a good guy and he just instructed us to add a box of baking soda to the pool. He said that we should turn the pump off.

The interior installer also said they used just shy of 2 gallons on our small pool when the ph was around 7.4 before the cleaning.
 

JamesW

TFP Expert
Mar 2, 2011
27,697
Increase the TA by 60 ppm and brush and circulate well for an hour and then retest.

If the TA is then readable, increase to 80 ppm and then recheck the next day for pH and TA.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,987
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
It looks like we'd need to add several pounds of baking soda to raise the TA to 80. Is that correct or am I missing something?
Try 7-8 pounds to start. Walmart, Sams, Costco sell big bags of baking soda.
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
Thanks for the advice! My husband is afraid to go too far from the interior installers recommendation so we are adding 2 more pounds (after the initial 1.5 pounds) and then will test before possibly adding another 2 pounds (so total would be 5.5 pounds). The interior installer asked that we test again in the morning and then he said he can stop by early afternoon.
 
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tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
Once we get the TA and pH back in line, do we have to worry about anything else (like elevated copper in the water)?
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,987
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
If that 0 TA water was in contact with any copper, it dissolved some of it. How much, hard to say. Only way to get rid of it is to drain and refill.
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
What does copper in the water mean in terms of causing damage? We are already planning on draining the pool in October/November so that the interior can be acid washed (to resolve some issues with excess "cream"). Would it be better to drain it sooner?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,987
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Copper in the water can stain the pool surface. You have to be careful not to rapidly raise the pH. That is why JamesW said to NOT use soda ash.

You may as well wait until you are going to drain in a month or two.
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
Thanks! That sounds like a plan. We ended up adding 3.5 pounds of baking soda and got the TA to 20ppm. Going to check things again in the morning and go from there.
 

JamesW

TFP Expert
Mar 2, 2011
27,697
I would get the TA to about 80 and then keep checking the pH, but don't force the pH up too fast.

Any damage from the low pH has already occurred.

Once the TA is at 80 ppm, the pH is essentially 100 times higher than it was before.

Maybe test the water for copper to see what the level is.
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
Thanks! I realized I have a broad spectrum pH test for gardening that seems to be showing a pH of 6.5 (this was after adding 3.5 pounds of baking soda last night). I just added 2 more pounds of baking soda and am going to the store to get more.
 
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tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
The interior installer is sending over his water guy to “fix it”…I suspect they are going to want to add soda ash and not sure I can convince them otherwise since they are the “experts”.
 

tippakayak

Member
Aug 4, 2018
20
Tucson, AZ
Much to my relief the water guy is a fan of TFP! We added in 5 more pounds of baking soda (so total added since yesterday came to 10.5 pounds). The TA is now 90, the pH is approaching 7.0.
 
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