I remember getting test results of 150 CYA and the pool store telling me, "The levels look good! keep shocking and bring a water sample in 2 days.".
I spent a lot of money, and no swimming. Last year, I spent little money and a lot of swimming. We are off to a great start this year again, we started swimming 2 weeks ago and we will go to mid October.
Don't put any other chemical except what you actually need. You need liquid chlorine, acid, sometimes Borax, sometimes Baking soda. Polysquat Algaecide 60, if you are doing a metal treatment.
Pucks are not bad, they are only misused. My stabilizer level is 30 right now. I can use pucks for a week or so and be okay and then switch to liquid. That's why getting your own test kit is important. I know how each chemical will affect the levels of the pool.