I need some advise as I think my local pool store is trying to swindle me. My 10,000 gallon in ground salt water vinyl pool started to turn slightly green (I could still see the bottom).

I added 1 gallon of liquid chlorine that states it's 10.5% concentration. The water initially turned darker green but the color began to lighten the next day. I had the pool store test the water and they measured 4ppm of chlorine and stated I needed to shock again. So this time, I purchase 2.5 gallons of the same liquid chlorine and add it too the water.

After 5 hours, I see no change in the water color, which is unusual as in the past it would have already turned a light grey color. So I had them test my water again and the total chlorine and free chlorine both still indicate 4ppm!

They tell me it's not unusual because there is algae in my pool which immediately consumes the chlorine and I need to keep purchasing and adding more until I kill it??

I believe they are full it but need someone more experienced to confirm. Here are the specifics listed on the last water test performed 5 hours after adding 2.5 gallons of shock:

TC - 4ppm
FC - 4ppm
CC - 0ppm
pH - 7.5
Total Alk - 125ppm
Calcium Hard - 100ppm
Stabilizer - 60ppm
TDS - 4000ppm
Salt - 2,900ppm