question after acid washing

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O

omsrex

0
Jan 21, 2014
38
El Paso, TX
Hi

so I just emptied my pool and acid washed it. I couldn't find any info on the process for adding chemicals after refilling. I have a swg. Do I just follow directions for a new pool with new plaster or should I perhaps do something a little different? Thanks for all your help in advance.
 
The plaster is fully cured and won't need to be treated like new plaster. I would get the pH and alkalinity right first. Then start bringing up the chlorine. Then add cyanuric, salt and calcium as needed. Keep the SWG off until you get a good balance.

If you can post fill water test results, we can give more specific advice.

Edit- Although the plaster should be fully cured, the acid wash might have exposed some calcium hydroxide in the underlying cement. Allowing the hydroxide to get converted into carbonate before adding salt might be worthwhile. If you want to be extra cautious, you could wait a few weeks before adding salt. -End edit.
 
Ok so I tested the water yesterday at 5PM

Ph 7.2
FC 0.2
TA 65
CH 90
CYA did not check since I just added some and know it take a week to register

I then added 1.5 gallons of 8.25 bleach this morning and 240lbs of salt

what do you guys think?
 
I guess you did not care for James suggestion on waiting before adding salt ....

You CH is much too low, but with the addition of the bleach, the rest looks OK.

What was your CYA target? Use that to determine your required FC level.
 

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Ultimately you want it in the 70-80ppm range, although it is usually a good idea to not try to do it all at once. For example, if I was starting with a fresh fill and have a SWG, I might target 50ppm with the initial dose and check it after a week and then calculate a new dose ... you do not want to overshoot.

So, how much CYA did you add? What was the CYA you were targeting? That is what should determine your FC level until you retest the CYA.
 
I put in 16lbs of cya. I was targeting 70ish. But that seems like a good idea. I should probably wait another week or 2 and test again so I don't overshoot. I have also spoken to some people in my area. they tell me that the CH is usually high since we have hard water in el paso, tx. Mine is 90ppm from the fesh fill. I am wondering if that is true then why would mine be so low. I also remember that last year it was usually around 300ppm and i never added any calcium to the pool. I wonder if the calcium is leaching from the plaster. DO you think I should wait and let it stabilze or add some calcium? My plaster was pretty rough when I emptied it to acid wash it, so we actually sanded it smooth. thanks
sorry for long and winded statement/question.
 
You are lucky that you water appears to be softer ... not uncommon. The CH will continually rise as water evaporates out (leaving its CH) and you add more water with new CH. But currently you CH is much too low for a plaster pool and could be damaging. I would get it up to at least 200ppm and keep the pH a little higher so the water is less aggressive.
 
The dihydrate just contains two water molecules attached to each calcium chloride molecule. That makes the dihydrate type about 77 percent calcium chloride. The only difference is that you have to use more of the dihydrate type.

You can use the pool math tool in my signature to calculate the correct amount.
 
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