Here is the pre-school version for us very newBs. Understand all this and accept it, or Trouble Free Pool website can be overwhelming:
FC is Free Chlorine. This is the chlorine available to kill bad stuff, backup chlorine ready and waiting. It is critically important.
CC Combined Chlorine (edit) is the chlorine IN THE PROCESS of killing bad stuff. Keep less than 1ppm.
CYA is Cyunaric Acid, also known as stabilizer. It is critically important. This keeps the sun from burning chlorine off too fast.
*****As CYA increases, the longer FC lasts AND the higher amount of free chlorine your pool MUST have at all times.
PH - try to keep it around 7.5.
SLAM is when you elevate the FC to about triple, and KEEP it elevated for many days to kill off all the bad stuff and algae. Keeping it elevated means testing FC often. Lower PH to 7.2 before SLAMming.
> If you don't test your pool by collecting a water sample and counting drops that you yourself add to the sample, then almost all of this is futile.
> If you are guessing how much chemical to add, then almost all this is futile.
> If you are guessing how many gallons are in your pool, then all this is futile.
> If you're pretty sure that liquid chlorine bleach isn't necessary, then all this is futile.
> If you trust a pool store's advice, then all this is futile.
I just learned all this after owning a pool for 10 years. So many helpful people here, with links in their signatures! Pool School and Pool Math are up top there for us to click. This is the OVER SIMPLIFIED stuff my brain just learned the last several days ONLY for those of us new to Trouble Free Pool.
Thanks for all your help!!!