new pool, mixed test results where to go from here

[Kowalski22]

hello all,
I am new to pools, just built a new salt water pool the startup guy is done. where to go from here?
pool details
21,500 gallons
pebble tec, salt pool
I am testing with a Taylor k-2006 fas-dpd kit and comparing to the local pool stores free testing.

my test results;
FC 2.8
PH 7.7
TA 50
CH have not tested
CYA 50
salt 3800 (according to Hayward panel)
water temp approx 82F

pool store test;
FC .86
total chlorine 1.51
CC .65
PH 7.7
CH 101
TA 51
CYA 47
phosphate 360
salt 3300

it seems the pool stores chlorine test vs my test is way off. these test results were from yesterday morning, I just tested the FC level again this morning at 2.8. according to the pool math app I need to add 13oz of acid (using 20 baume) to get the
ph level to 7.4.

according to the Taylor water gram my water is corrosive. seems I need to add calcium chloride and possibly up the TA as well. So where should I begin?

 

[mknauss]

Welcome to the forum!
We will use your test results.
Test your CH. You need that as you may need to add some calcium.
Let your pH rise to 8 prior to lowering to 7.6. This will happen pretty quickly with a new plaster pool. Monitor your TA as you need that for how much acid to use plus you may need to add some baking soda if it drops anymore.
Up your FC to follow the FC/CYA Levels. You can add 20 ppm worth of CYA too.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.