Recommend draining or wait another year

Jan 30, 2019
8
Arizona
Pool Size
12042
Surface
Plaster
Chlorine
Liquid Chlorine
Hello all,
The last time I drained my pool has been 5yrs. Thinking of draining this year, or wait one more year.
I have a Taylor 2006 test kit.
My readings:
FC :3.5. CC:0
PH: 8 +
TA:130
CH:650
CYA:70
I definitely need to add Muriatic acid to bring down my PH and TA. Before that though would you recommend I drain all my water to start fresh or half? Or none? Thanks so much.
 
You must be dumping a lot of water often as your CH would be much higher after 5 years. That is if you live in the Phoenix area.

If at 650 and only going up that much each year, you can wait a year.
 
Where in Arizona?

What is the pH, TA and CH of your tap water/fill water?
Do you have a functuoning water softener plumbed to your autofill?