First off, thanks to everyone who contributes to this site. It has been extremely helpful as begin to figure things out with our new home and the pool it came with.
The pool is pretty clean looking, clear water and nothing visibly wrong. I took apart and thoroughly cleaned the DE filter and the grids. It was pretty nasty and there were some small areas of visible green algae starting to form. Nothing overwhelming but present in areas. Now that it is clean, the pressure is in the 12 -13 range which looks to be normal based on markings by previous owner.
My next step has been to try and balance the water. It has an in-line chlorinator (3" pucks) but after what I have read here, I am thinking to avoid the "shock" and puck products and go with liquid bleach from Costco. I have been having a **** of a time keeping chlorine in the pool which led me to believe something is hiding and growing somewhere and eating the chlorine. I got the chlorine levels up to ~22 or shock level (given CYA 75-80) only to see it drop off to around about 24 hrs later. My CC was 0.5 so I didn't expect a huge drop like this.
I decided last night to and hit it hard and start officially a SLAM process and brought the chlorine level to 25ppm (around 8pm last night). I woke up this morning and measured only 11ppm chlorine. For such a clean looking pool, this seems extreme.
I again put more bleach in this morning to bring it back up to around 24.5 and will check again in another hour or so to see where I am at.
My CYA is between 75-80, pH around 7.5, and TA around 100.
Is this much overnight chlorine loss abnormal for a pool with what I thought was a minimal issue?
Thanks again for all the advice.