VERY rapid scale buildup on salt cell... why??

I have a one-year old CircuPool SJ series salt cell. About a month ago, I got a new vinyl liner for my 25,000 gallon pool (with attached spa). So it's a fresh fill, to which I carefully added calcium hardness, alkalinity up, salt, and CYA (in the form of Instant Conditioner). My current levels are:

Total alkalinity: about 110
Calcium hardness: about 250 (although my Taylor result goes from red to a VERY pale blue that's almost clear, but AquaChek test strips seem to corroborate 250)
PH: 7.6 (although it tends to creep up, so I've been maintaining 7.4-7.6 with dry acid about once a week)
CYA: about 40
Salt: 3700

We had a lot of cool weather, then a sudden couple days over 100. Pool temp reached 89. Since then the pool temp has been hovering in the low 80s.

My cell had some white scale on it -- not thick or anything, but definitely visible, especially on the edges. It does seem to affect my cell's performance, since even at full power (but not boost) my chlorine levels weren't getting above 3 ppm without adding liquid shock. So I cleaned it. Then, only a day later, it was back. Cleaned it again. A day later, same thing. Why is this happening? I've heard that warmer temps can cause calcium to precipitate out onto cell plates, but I don't think my calcium and alkalinity levels are high enough for that.

Thoughts?

I should add that last year, when the new cell was installed, my water levels were very similar -- the calcium may have been slightly less (more like 200-220), and my TA hovered around 100. PH last summer also constantly crept up and I had to manage with dry acid about once a week to keep it at 7.6. But I didn't have scale building up like this on the cell.