I'd like to understand the CSI and corrosive to plaster aspect a bit more in depth.
The impetus for this question is that this is of course winter and pool temps have plummeted. Since temp can't be controlled, only pH can be. CH and TA also play a role obviously, but even a 0.2 difference in pH can be the difference between "ok" and "corrosive" at low water temps. My water temp is currently 46.
Additionally, playing with pool math show essentially to keep pH at 7.8 or 8.0, but since the testing materials only go to 8.0, you don't really know if you're at 8.0 or above that. Getting much above that isn't any good either.
My TA is currently at 60. CH 320.
It's truly "amazing" how little muriatic it takes to drop the pH. 4 ounces into 12,000 gallons of water can dump pH 0.4. My pump/water feature run 12x7 so it does go back up if it drops too low.
So that brings up the real set of questions.
- How long does "corrosive" take to cause damage?
- What visible changes would I see for damage? Or is this accumulated damage over years and it really only results in a reduced life span of the plaster 10 years from now?
- What are the instant vs. cumulative effects of "corrosive"? For example, if I got too much MA in there and my pH went down to 7.6 until it aerated back up I would be "corrosive" If that process of going back up took .... say a day... would my plaster be totally screwed? Or would it be the accumulation of 200 of those days over years that would cause the damage?
I know there are some experts out here who say to ignore CSI, there's no use for it, they've never calculated it, etc. I am not trying to knock that approach. For *me* however, it's a valid indicator of keeping several distinct parameters in range as they interact. I also find the science behind it interesting and would like to understand the short and long-term impacts of occasional "dips" into the corrosive phase of things.