Filling up pool for the 1st time


Bronze Supporter
You have a vinyl liner pool. CSI (and low CH) do not matter. Turn off the CSI tracking in Poolmath.
? this article (attached pic) from TFP mentioned that to keep the CSI at 0 to -0.30 to prevent scale build up at cell plates. So you mean there is nothing to be concerned of even my current CSI is -1.21? (Refer attached pic)

Given that I have already purchased the Calcium Chloride Flake and there is no way I can return it, adding in the calcium chloride do no harm at all, at the same time, provide no benefit at all?



Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
With a vinyl liner, CSI on the low side is of no consequence. With yours at -1.2, your SWCG is fine too.

You can add some calcium if you like. Be prepared for it to cloud your water for a day or two when you add it.


Bronze Supporter
@mknauss now I understand! CSI < -0.6 will cause corrosion to plaster, tiles, etc, while CSI > 0.6 will cause scaling to the SWG plates. Since my CSI is -1.21 and I am having a vinyl pool, there is no issue for me. ??? thanks a lot! Now I need to get rid of my 25kg calcium chloride flakes ?
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