New pool in rental home, levels odd, questions about order of ops

[Aaron B]

Thank you all very much for your assistance and pool school last year when we set-up our above-ground 'starter' pool last summer.
This summer we are moving into a rental place (to renovate our house and hoping to add an in-ground pool!) at a neighbors home and his house is the 'party and pool house'. SO, I want my pool here to be as bright and clean as last year's at my home.
My test results from yesterday are:
FC=2 (CC was 4 which was odd to me), so Total Chlorine was 6.
PH=6 (turned yellow immediately, so I used some Kombucha Ph strips to help)
TA so low I couldn't record it using the tools I have (turned pink immediately, never could get it to turn green)
CH=125
CYA=80.
I thought I would start with draining some water to lower the CYA before tackling anything else. Yesterday I drained what appeared to be about 2 feet (25%-ish of total volume?) and refilled this morning. The CYA is *still* 80, which is disappointing.

Should I try drain and fill again?

Also, I checked out the pump system and it appears that they have an auto-chlorine in-line feeder, and they also appear to use trichlor pucks in a floater, and the owner reported to put a cup or two of bleach in every week. I don't know if the in-line feeder has anything in it, the owner didn't mention it, although I can feel the water move through it when the pump is on.

The pool filter itself appears to be a large cylinder about 3 feet high, called Hayward Cartridge Filter

What do y'all think I should do first? Re-drain and fill? Then tackle the PH, then the Chlorine?

Thanks so much!
-Aaron
Update to clarify: The pool water was clear with no indication of algae, currently draining and will engage in refill later today.

 

[mknauss]

Welcome to posting on the forum!
You need to drain more. You can go down to 12" of water left in the shallow end.
Then test pH and TA. If still low, you need to get that up. The unbridled use of the trichlor pucks has made the water vinegar and it is destroying the liner.
Come on back after doing another drain and refill.

I suggest you read ABC's of Pool Water Chemistry.

 

[IceShadow]

Looks like heavy puck use. Acidic pucks crash the pH, remove any TA buffer, push the CYA way up.

You have the right of it. Exchange out the water to get the CYA down to about 50 or so. How does the water look? If it's green you could start with getting CYA down to 30 or so to use less chlorine during the SLAM, but otherwise 50 is probably appropriate for your climate.

Once the CYA is down you'll need to add enough baking soda or soda ash to get the TA up to 50. Then you can address the pH and FC levels.

 

[Aaron B]

Thank you for both very much for your input and advice. I drained/refilled yesterday and this morning the CYA was 40-ish, which is a Huge improvement! I raised the TA to 65, and this felt safe enough to start the SLAM which I started just now, after brushing the sides/floor and skimming. I will brush/skim again in about 2 hours and re-test, then do the overnight test and see what I've got going on in the morning.