It doesn't make sense that you would have any calcium buildup with a CH of 250 and a TA of 80...just not high enough. If your CH was 500 and your TA 200 I'd buy it.

I think you have another cause of the buildup. You could try the low pH thing--but do NOT let the pool get below 7.0--and don't try it unless your test kit measures BELOW 7.0 (like 6.8). Because when pH measures at the lowest level it could be far lower, and anything below 6.9 is dangerous to vinyl liners.

Do you actually SEE anything, like cloudy water? Is it pretty clear, totally clear, or crystal clear (where it seems to sparkle like a gem)? I'm guessing here, wondering if something else is in your water....