Now I am thinking about adding boric acid

[demarco]

Okay so its been about 40 - 50 days after the pool has been replastered. Now i am thinking about adding boric acid.

My numbers are

pH = 7.6 (it moves up 0.1 or there abouts every day)
FC = 4.0 (drops about 0.60 ppm per day)
TA = 50
CH = 160
CYA = 40

with those numbers my CSI = -0.24

So i wanted to add boric acid up to 50ppm, for my pool 18178gallons, thats 43lbs of boric acid.
THis is all from the pool calculator. All of my numbers are good, except the CH is too low,

Wet edge (makers of the plaster) and the pool builder say that i should keep the pH at 7.6 but with the borates and my current CH the CSI = -0.3 which is "Potential to become corrosive to plaster"

But if i raised the CH to 250 my CSI becomes -0.14, which is balanced again.

So my "plan" is to raise the CH to 250 then add the boric acid.

The alternative is to leave the CH as it is adjust the pH to 7.8 (new target) then add boric acid.

So what should i do???
Vince

 

[chem geek]

Re: So you want to add borates to your pool--Why and How

The boric acid will somewhat lower the pH so if you don't want the pH getting too low then raise the pH first before adding the boric acid. As for the CH, you can set that to your target and might as well do that before adding boric acid though that's not a big deal doing it the other way around.

 

[JasonLion]

I suggest you don't worry quite so much about CSI, and instead try to stay within the recommended levels.

 

[demarco]

I suggest you don't worry quite so much about CSI, and instead try to stay within the recommended levels.

Okay seems that you are all saying is to increase the CH to the recommended levels. sounds good to me.