What is your ta?
Any ta 50 or over doesn’t generally need adjustment- just keep ph in the 7’s, as u add acid to do so the ta will lower.
Ta is the last parameter to worry about.
There is no “perfect TA” you just need to know the value so u can calculate acid doses for ph control in
PoolMath
Stabilizer/cya doesn’t lower fc. It is acidic so it can lower ph a little (use effects of adding in poolmath to see the effects of all chems on each parameter BEFORE adding to get an understanding)
Cya is “sunscreen” for chlorine but also binds some of the “active” chlorine so the fc level needs to increase as you increase your cya level to achieve adequate disinfecting amounts
FC/CYA Levels
www.google.com
Cya level is lowered by water replacement & degrades slightly over time with high water temperatures
I have a spa & a pool so I buy large bottles of r-0871
Yes- You need to test fc daily until u get familiar with the daily fc consumption of your pool at which point you can go a couple days. Be aware that the average pool uses 2-4 ppm of fc daily, this must be replenished. However u choose to test & dose, you MUST ensure that you don’t allow fc to fall below minimum for your cya level before your next dose lest nasties will grow

. Skirting minimum is not recommended. Most dose to high target

or a scootch above to ensure minimum isn’t broached & to have a cushion incase of higher bather load, high uv day, or other environmental factors.
It is safe to swim w/ fc levels anywhere between minimum and slam level for your cya so long as you can see the bottom of the pool for swimmer safety.
If the power chlor is the bioguard stuff it is only about 70% trichlor
(trichlor increases cya, & is also acidic)
It also contains borates “Boron sodium oxide (B4Na2O7), pentahydrate”
(which can increase TA)
& “trade secret clarifiers” - not recommended.
Basically it’s very expensive reduced strength trichlor.
“Multi purpose” products like this make it hard to keep track of what they will do & have done to your water.
It’s much easier to test & adjust each parameter on its own.
If u want fc - add liquid chlorine or use a swg.
If u want cya - add cya.
If u want borates - add boric acid.
An ounce of prevention is worth a pound of cure - this holds especially true with a pool & daily/regular testing vs once a week & trying to fix everything that occurred over a whole week in one day.