Scaling on cell...why?

[mas985]

The "correct" PH depends on other factors like TA and CH which is why I suggested the calculator. However, having a negative CSI does not guarantee a scale free cell, only reduces the likelihood. You could try lowering the PH a little and see if that helps (i.e. keep CSI between -1 and -0.5) which should not be a problem since you have a vinyl pool. Also, it would be a good idea to make sure you are actually getting scale and not something else. Scale is indicated by fizzing when immersed in a acid solution.

[JimK]

The "correct" PH depends on other factors like TA and CH which is why I suggested the calculator. However, having a negative CSI does not guarantee a scale free cell, only reduces the likelihood. You could try lowering the PH a little and see if that helps (i.e. keep CSI between -1 and -0.5) which should not be a problem since you have a vinyl pool. Also, it would be a good idea to make sure you are actually getting scale and not something else. Scale is indicated by fizzing when immersed in a acid solution.

Thanks for the advice on where to keep CSI. Having that range to shoot for is helpful. Right now I'm at -.77. Using the calculator it's interesting to see how much effect temperature has on CSI. Something else I think should help is I expect my CH level to drop since I do not plan to use cal hypo this season, just plain bleach when I need to shock.

Regarding the use of Jacks Magic Purple Stuff, do you think it is helpful in preventing scaling?

If I see more "scaling", I'll take a sample and put it in some acid solution to see if it fizzes like you mentioned.