Need help with my big mess of a pool

Well, been so swamped with worked i'd taken the easy way out this year by using tri-chlor tabs instead of my usual bleach, and was still using 2 yr. old K-2006 Taylor test kit re-agents to test but only about 1x a week. I knew they were probably not great so went to test strips. Anyway, just got my new Taylor kit today and boy is my pool messed up.
Here are numbers

Chlorine 20
PH 8.0
Alkalinity 180
CYA above 100- I can't tell exact number

The chlorine has me baffled as I was putting in 3 tabs a week around and when they dissolved i'd put more. I just wasn't testing enough. I haven't put any tabs or chlorine in over 1 week. And it's 20! I can only guess what it was last week.

Got a lot of moving parts here so was going to start with this plan.
1. Lower Chlorine to reasonable levels
2. Get Alkalinity down with muriatic acid
3. Stop using tabs and go back to bleach.
4. drain my pool a bit to lower CYA

Does this sound like a reasonable plan? Thanks.

Sounds like a reasonable plan, I will give my 2 cents worth on a few things.
1. Drain first, that will drop your CYA and TC readings once you refill. Go from there.
2. Use muriatic acid to drop pH. Alk will also drop, but measure pH while dropping with MA.
3. Test strips are so inaccurate, you would be better off with old reagents.
4. If you can put trichlor tabs in 3x/week, you can manage your pool with bleach 3 times a week.

Yep. Thanks for input. I think sounds like a plan.

Sorry you haven't had more input. How is it going?