So I'm going to have to drain it?

[acd]

Bought the Taylor FAS-DPD and came out with:

FC: 3.5
CC: 0.5
pH: 7.2
Alk: 110
CH: 900 (tested x 2)
CYA: >100 (tested x 2)

I live in the Phoenix area and have a pebble pool, so draining shouldn't be an issue. Do I just run the backwash line to the street gutter and go for 50-75% drain then refill with hose water? Any other recommendations?

 

[Texas Splash]

Ugh. That stinks. No doubt that CYA needs to be lowered. If you can reduce the CH at the same time without local water adding it right back that's a bonus. But for the CYA, you might want to do this first:

CYA Dilution Testing:
Add pool water to bottom of sticker.
Add tap water to top of sticker.
Shake.
Pour out half so mixture is to bottom of sticker.
Add reagent to top of sticker.
Shake.
Test outside with back to sun and tube at waist level.
Pour back and forth a few times to see if you get the same result.
Double the result.

Often times it's good to know "how high" your CYA really is over 100. If you have no algae (any cloudiness or green), lowering your CYA to about 70 should work well this time of year. If you have algae, you might want to lower CYA to about 50 for a more manageable SLAM. But yes, you can backwash to waste and drain that way as long as you have a main drain. If all you have is the skimmer, then you'll be doing the hokey-pokey (little drain/little fill routine) unless you have a separate submersible pump.