Question on Pool Calculator

[rogerbrks]

According to the "Waterbalance for SWGs" page in Pool School, it list numbers that my numbers should fall within. When I use those numbers in Pool Calculator the results are scored at -0.66 and states "Corrosion of plaster likely". Have I missed something?

 

[JasonLion]

The lowest I can get the CSI to go using the Pool School balancing for a SWG numbers is -0.55. That happens with:

PH 7.5
TA 70
CH 300
CYA 80
Borate 50
Salt 3600
Temp 80

Keep in mind that this is with all of the suggested ranges moved to which ever side of the range gives the lowest CSI value. Switching to the other side of each suggested range gives CSI numbers much closer to zero.

If your water is colder than that, you should not let the PH go that low. Also, when using borates and keeping the salt level on the high side it might be a good idea to raise CH a little, say to 350.