Help! New pigmented plaster & 3rd No drain acid bath...

[carl292]

Hello l All,
On 5/20/2022 our 23500 inground pigmented replaster was completed and filled with tap water. Their chemical guy came out the same day and added sequesterents and 12 gals of muriatic acid. The following week there was still alot of swirls and cream as they called it that did not come out. So they did a 2nd bath and a week later with the same amount of 12 gal... Ughhh
Still not much came off of the swirling and cream.
So on Tuesday this week, the owner added 24 gals of muriatic acid ( yes 24) / scaletec and would be back out Thursday to neutralize it. He added 6 lbs of baking soda and said to add maybe up-to 10 more lbs Friday morning. So i did and noticed the Ta and Ph didn't move later that night at all. I have a TF 100 kit.
Wanting to check his numbers on the calculator here. I converted the 24 gals of acid to oz and got 3072 oz and plugged into the calculator here showing the effects of adding chemicals based on my pool dimensions. It said 3072 oz of acid would lower my Ta by 511. I plugged current -511 and target of 80 into the calculator and i'll need 3261 oz of baking soda to get there which equates to 203 lbs of sodium bicarbonate. The pool finish looks great, pool super clear up until today when I added 25 lbs of arm hammer baking soda. Now it's pretty cloudy. So between Thursday and today we've added 39 lbs of baking soda by walking arounds the pool. Whats the most that can be added per day safely to get this nite mare neutralized so the acid is not still working of the finish and get my Ta Ph back to where I can get a read on it.
Thanks

 

[mknauss]

Add 60 ppm TA worth of baking soda. Let that mix for a couple hours and brush. Test pH. If not readable, repeat. Keep repeating until you get a pH that is readable by the comparator block. Then test TA.

 

[carl292]

Thx mknauss -
If you could please confirm if I am correct with my math. So to add 60 ppm Ta worh of baking soda in pool calculator. Leaving the now at 0 and target range at 60 = 331 oz or converted to 20.68 lbs. On the repeat process you mentioned. How much in the repeat process is acceptable to add in 1 day scenario.
Just making sure Thanks

 

[mknauss]

That is the right amount.

I would test TA along with pH after each addition. TA may get positive before pH rises into the 7's. Once you get positive TA, let the pool circulate for a few hours and test pH.

You can do this every hour or so, as long as you mix the pool water really well. High pump speed, brushing, etc.

 

[carl292]

Ok perfect. Stayed tuned

 

[carl292]

Update:
I checked the Ta reading around lunch time and we're at 90-100 Ta. Did it 2x to make sure! Ph was not the yet as of 6pm barely 6.8. Still a bot on the yellow side.
Being that i added 20 lbs this morning at 7 is it reasonable that Ph should climb a bit overnight and get a bunch closer tomorrow or will something else be needed to get it within range ? Thx

 

[mknauss]

I would let the system go until tomorrow. With that level of TA, your pH should rise. If it does not by tomorrow, use Borax to raise the pH in little jumps. Say 0.4 pH jumps.

Brush the pool really well tonight or tomorrow morning before checking chemical levels again.

 

[carl292]

Ok since yesterday and today, Ta is staying at 90 and my Ph is not as yellow on the color chart as of this morning. I'd say maybe 6.6. So to increase in .4 increments to 7.0 using borax. Calculator is saying 268 ounces which is 16 lbs. Is that what I should put in all at once? Would it be good to run pump 24 hrs to clear up all the baking soda thats settling over the last couple days. Pool is very cloudy

 

[mknauss]

There should be no baking soda undissolved.

 

[mknauss]

I get 5 lbs of borax to raise pH by 0.4.

 

[mknauss]

I suspect calcium scale has precipitated.

 

[carl292]

Ok adding 5 lbs of borax. Sounds like i need to run the pump 24 hrs a day to clear it up. I think its baking soda that has settled

 

[mknauss]

It cannot be baking soda. Sodium bicarbonate will completely dissolve unless the TA is extremely high.

 

[carl292]

The 3rd no drain acid bath consisted of 24 gal of muriatic acid so my Ta was so low that when testing it would straight to red and not the green alkalinity agent. So over a couple days and 90lbs of baking soda added could it be unused baking soda. The water was so acidic. Ive been beenising my TF 100 testing 3x a day and TA is at 90 (??) When i clean the filter its like a yellowish dirt there and same when i brush

 

[mknauss]

It is some other kind of precipitate.

The acid washes were not a good idea. I suspect your plaster will not have a long life.

 

[carl292]

Just checked the Ta and i'm at 110. Hopefully the 5 lbs of borax get Ph more inline. So frustrating trusting pool contractors