Pool Replaster Day 8-

HiddenRiver

Gold Supporter
Bronze Supporter
Jun 15, 2017
351
East Coventry, PA
Folks I need a sanity check. Our pool replaster is in day 8 of curing process and we have been brushing and trying to balance since this time. Today I was able to add more CYA to get that level up to 25. But I continue to have trouble getting my pH down and alkalinity down. Today I was able to get pH down to 8 but alkalinity went up and hardness went up. Unfortunately we think we buy enough chemicals and then find (like now) we need more and the pool stores are running out of the chemicals. Especially the 20 Baume liquid acid, had to add dry acid today because couldn’t find liquid. Just now this is my result:

free Cl. 1.5
CC. 0
CYA. 25 (up from 0 yesterday although I added a gallon yesterday, added two more today)
Alkalinity 170 (up from 140 yesterday)
pH. 8.0 (down from 8.2+ yesterday
CH 200 (down from 250 yesterday)
CSI is +0.25 down from 0.80 yesterday

I know we need more acid. Am I doing something very wrong what do I tackle first and where can I get more liquid acid?

thank you
 

markayash

Gold Supporter
Mar 21, 2016
2,697
Atlanta Ga
When i did my mine few years back I added 2 gallons of acid as soon as it was full and pump was running. We will see what the experts think.
Also I don’t think you should be too concerned with CYA yet
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,219
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
If the dot disappears in the CYA test between 30 and 20 we round up and call it 30. The scale is logarithmic and you cannot eyeball values between the lines.

What CYA do you want? CYA 30 is fine for a startup.

Your chemistry looks fine. Don’t worry about the TA. Just keep the pH in the 7s and the TA will come down in time.

What startup guide are you following?

 

HiddenRiver

Gold Supporter
Bronze Supporter
Jun 15, 2017
351
East Coventry, PA
If the dot disappears in the CYA test between 30 and 20 we round up and call it 30. The scale is logarithmic and you cannot eyeball values between the lines.

What CYA do you want? CYA 30 is fine for a startup.

Your chemistry looks fine. Don’t worry about the TA. Just keep the pH in the 7s and the TA will come down in time.

What startup guide are you following?

Thank you! I had started with the installers instructions and now I am using wet edges (manufacturer) instructions. Are all acid sources the same? Is there a place you know of to get the needed acid outside of pool suppliers who appear to have none in stock?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,909
Laughlin, NV
It is best to NOT use dry acid. The sulfates will build up in your pool water and cause issues.

Paint stores, Home Depot, Lowes, Ace Hardware, etc all carry muriatic acid.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,219
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Muriatic Acid is preferred to dry acid. Dry acid is sodium bisulfate. After dissociation of the acid salt, it leaves behind the sulfate ion.

Problems sulfates can cause include:
  • Sulfates can damage concrete & plaster
  • Excess sulfates in water increases the likelihood of corrosion on metal parts
  • Excess sulfates in splash out water leads to degradation of any concrete surfaces
  • Sulfates degrade the coatings on SWG plates
  • At high enough concentrations, sulfates can react with calcium to form spindly, needle-like crystals of calcium sulfate (gypsum)
  • While sulfates in vinyl pools is typically not as problematic as in plaster pools, scaling of gypsum crystals can increase the risk of liner puncture.
Sulfates can only be removed by draining water.


You can find Muriatic Acid in hardware stores - Home Depot, Lowe’s, etc.
 

HiddenRiver

Gold Supporter
Bronze Supporter
Jun 15, 2017
351
East Coventry, PA
Does anyone have thoughts on how to prepare the water and pool for winter closing after the 28 day cure? Is this something the manufacturer would have recommendations on?