First post - great forum full of lots of good advice!

Just spent an agonizing weekend draining, acid washing, patching, refilling, and balancing my pool. What led to this was my running it on auto-pilot for 6 years with no water changes; finally got my water tested and found a TDS > 3000 and a CYA greater than 1000 (I think that is what he said, but maybe it was 100). Regardless, a lot -- needed to change out the water. Eventually led to nasty purple staining which was the straw that broke the camel's back.

So I'd *really* like to avoid (or at least defer for as long as possible) the pain of big water changes. I've been using the trichlor pucks, which from this forum I now know inexorably raise your CYA. So I'm considering going the bleach route, once I've used tricholor long enough after the water change to get my CYA to ~30 ppm. But if I go to bleach, according to the pool calculator, I'm adding a lot of salt (TDS) with every bottle. That too will build up and force a water change. So question is, which is the lesser of two evils? Go with the trichlor and change water due to CYA, or go with bleach and change due to high TDS?

Pool info: 25k gallon in ground plaster pool with attached spa/waterfall in between. Fresh water 2 days ago - latest numbers from my (non strip!!) test kit:

FC 3
TC 5
CH 70 (need to get this up -- that's the next trip to the store)
CYA <30 (can't measure with test kit)
TA 100
Ph 7.4