Adjusting CSI with temperature?

[matj6876]

Trying to stay half a step ahead of the game; I was wondering what to do as the pool cools off this fall and winter.
I'm in TX so I'm not going to close it but have noticed that as the pool temp falls my balanced numbers now:
pH 7.5
FC 5
CC 0
TC 5
TA 90
CH 340
CYA 40-50
Salt 4400
Temp 86F
CSI -0.17 ("balanced")

...become more and more (potentially) corrosive, or negative.

I know that CSI is affected by many factors but it would seem that pH, in this instance plays the biggest part.
Is the solution to this, low temp, potentially corrosive CSI just to let my pH drift up (as it naturally does - SWCG!!) to around 7.9, as opposed to 7.5 as the temp falls? Or am I over simplifying things?

Thanks again in advance.

 

[chem geek]

The good news is that you normally don't have to worry about the variation in the CSI with temperature because as the temperature falls, the pH goes up on its own keeping the CSI more stable (it drops only a small amount). For example, at standard parameters of pH 7.5, TA 100, CYA 30, a drop in temperature from 85F to 55F causes the pH to rise to 7.7 so the CSI drops from +0.07 to -0.01 which isn't very much.

So I wouldn't worry about it -- you should not need to adjust your pH at all, or if you realy wanted to you wouldn't do so by more than about +0.1

Richard