No, I don't have a SWCG, just using bleach or LC now. Up until I hit this forum (about 4 weeks ago) and converted, I was using a Pool Frog inline chlorinator, which used tri-chlor cartridges (and would raise the acid level as I understand), but I don't use that anymore.

Regarding calcium, here's what I wrote in the previous post-

drained and refilled completely last May, which lowered the CH considerably (in fact I had to add calcium to raise it to it's current level of 190)
Prior to that, I don't know what the CH level was, as I never tracked it

So, would you say that I should keep my TA level at it's current 80 or higher? That would make sense to me for concrete, as you say.

Dan