Yesterday Vacuumed To Waste dead algae, sand, debris so bottom Is pretty clean and added water as needed. Added about 25 lbs shock 10 lbs at a time. And got the same result of clouds then no free chlorine. I also realized in testing the water that the PH was 6.2 and Total Alk 40. The CYA is now Below 30 and last week it was in the 30-50 range. Also, I'm running Hayward 700 sq foot DE filter, after a few hours it has to be backwashed, goes from 25 to 30+ PSI. Backwashed 4 times in past couple of days. I didn't want to keep adding chlorine and using up the rest of the 50lb bucket, so I went to Leslie's for Alk/Ph Up. They tested the water and said the Nitrates are high at 30 ppm, and they said that is why I can't get the chlorine up, so they said the first thing to do was to drain and fill to get the nitrate level down. I don't really trust that is the full problem, so I started looking around online and found the TFP forum.
At this point I have spent more in chemicals than it would have been to empty the pool and re-fill it, so I'm thinking I should just drain half as it should help.
I don't have the Pro test kit, but have AquaChek 7 strips which have been accurate for the the past couple of years. They test Hardness, Total Ch, FC, PH, Toltal Alk, and CYA.
I can really use some help finding the most economical and/or best way to get the pool clean. It does not look like I will be in the spa on Father's Day!