Does CSI need attention here?

[HoustonMom]

Hi all. Today I noticed a message on Pool Calculator: "Potential to become scaling" which is prompting me to write.

I could use some direction on managing CSI and on keeping TA at an ideal level. My PH has a tendency to climb, and the pool likes it at 7.8.

As a test I input some approximate numbers of what my pool numbers seem to be these days:

FC 7
pH 7.8
TA 90
CH 450
CYA 50
Temp 90
CSI .49

My actual numbers as of now (1 pm) are below, giving the exact same CSI of .49 (but I didn't see the scaling message from before for some reason):
FC 8.5
pH 7.8
TA 90
CH 450
CYA 50
Temp 91
CSI .49

Additional information: The CH of our tap water is 110. I have never measured borates, is this a factor here?

Finally, I tend to keep FC in the range of 7.5 in the evening, falling to around 5 by the next evening.

If anyone has suggestions for me or can direct me to the right reading material, I look forward to your reply!

Thank you in advance, I really appreciate the advice on this forum! HoustonMom

 

[Richard320]

That's easy to fix, and you're at the point where you should fix it. pH of 7.8 means time to add acid to bring it down. That will also lower the CSI.

Play around with the pool calculator, plugging different values in and watching the CSI. You'll soon see that the CH affects it, but it's hard to fix; Temperature affects it, but it's also hard to fix; TA takes time to fix; pH is the fastest, easiest fix - and yours is already right at the top of the eye comfort zone.

 

[jblizzle]

I agree with Richard, if you lower the pH the CSI will be improved (although you are not out of range now).

One option to further help would be to Lower the Total Alkalinity following that process. That will lower the CSI and also should slow the rate that the pH rises.

 

[chem geek]

If you had a saltwater chlorine generator or were using The Liquidator, then the higher CSI that you have could be a problem for scaling in those systems, but otherwise you might not see scaling at +0.5. The other potential problem area would be if you were using a gas heater since the temperature at the surface of the heat exchanger is around 30ºF higher than that of the pool water. We generally don't see scaling on pool surfaces until the CSI gets to +0.7 at the lowest or +1.0 where most pools would show scaling.