I just completed my first SLAM so now I'm the local expert!
My next door neighbor was complaining of algae but luckily had not yet been to the pool store. I took my TF-100 over to see what was going on. I definitely saw algae and these are the numbers for their 20,000, concrete, in-ground pool with 1.5 hp motor and Hayward DE filter:
FC: 0 Added enough chlorine to get 12ppm overnight and then revised to 16 ppm this morning
pH: RED!!! Added acid to 7.2
CH: 150 (They refill the pool using softened water)
We started about 5:00 pm yesterday and have made tremendous progress. Yes, they do think their neighbor is a little crazy and I completely overwhelmed them describing the kit and the TFP philosophy. They are pleased with the results that are coming quickly!
Their maintenance regimen is to drop 3 pucks into the inline dispenser every 3 days and to take a water sample to the pool shop every couple of weeks. That's it! No testing of chlorine or pH. No recollection of ever adding muratic acid or anything other than shock and algaecide (powder) when required which is a couple of times a year. This has gone on for years with not too many issues until now. Apparently, the algae is returning about every 3 weeks.
Unfortunately, I didn't take a picture of the starting condition which was moderately bad with algae on the pool floor and around the water line. There was algae on the walls because I'm now seeing it come off when brushing.
It was quite overcast yesterday and I read the CYA to be about 30. I did the CYA reading again this morning and read it at 40.
Time to go back over and check the chlorine level and do some brushing.