Can't get crystal clear water

[Darmani]

Hi group! Newbie question with Intex sand filter and salt water system. We were away from home for 2 weeks. No brushing or cleaning entire time just pump on. Chocked the pool, brushed few times and vacuumed. Water levels were OK. I read multiple articles and it's recommended to a liquid chlorine to increase FCI.
I added 0.5gal liquid chlorine at night and ran pump and boost for 24hrs. Still same slight algea in the bottom. Brushed and skimmed the pool, collected some algea bubbles. Liquid chlorine increased FCI to 10, but decreased Alk to 40 and pH to 6.8. TH level is at 250.
Backwashed the filter and water looked clean. What are your recommendations?

 

[HermanTX]

The only effective method to kill algae is to increase FC but you must know your CYA level.
How do you test your water. Look at Test Kits Compared
You need to follow the SLAM Process. Not sure why you decreased TA and pH. Algae is the issue.