Pool levels question

[Michael57]

Hi, can I get some opinions on my levels? They're currently:

FC 4.5
pH 8.0
CH 525
TA 90
CYA 50

I need to get a thermometer, but I'm guessing the water temp. is around 65-70F? In that case, I think the CSI is around .52? It seems my CH is getting high and should I be concerned about the CSI?

I need to add chlorine and muriatic acid right now to lower the pH, I usually target about 7 FC and 7.8 pH, would that bring my CH and CSI back into an okay range? Thanks!

 

[kellyfair]

Sorry, I can’t help with the CH issue, as I don’t have a plaster pool. I agree that your ph is getting too high.

 

[bmoreswim]

Yes .52 is your CSI. Good job. The easiest way to check for CSI is to open your last test result and change the pH and the new CSI appears. You have a narrow range of ph from 7.2 - 7.4 that keeps your CSI below 0. It can go a above 0 but then keep an eye out for scaling or cloudiness. So I’d shoot for 7.6 as your high point. Since you know you have higher CH, I would not tempt fate and keep CSI towards the high end of the Pool Math CSI range of .6. FC doesn’t affect CSI. But ultimately scaling and cloudiness are what you are trying to avoid.

 

[Michael57]

Thanks, I don't appear to have any cloudiness, but the pH typically will slowly rise over time. It will typically go from 7.6 to 8 over a couple weeks or so. Is this normal? It's hard to tell about the scaling as it appears to already have some on the tile that's at the water line (from the previous homeowner, I've only been here a few months). Thanks again

 

[bmoreswim]

Good follow-up information. Given that you have some minor scaling already, you want to keep the CSI from 0 to -.5 all the time. Yes, in most pools pH tends to rise somewhat over time. Completely normal.

For the record, your chlorine additions are liquid chlorine?

 

[Michael57]

Ok thanks, yes only liquid chlorine since I moved in.