I hear this every time I go to the pool store.
I get a bunch of conditioner, Shock, etc.
Everything Dies, and the pool is perfect.
Have a pool party ~20 kids
within 3-4 days, the green stuff starts growing.
I take in my sample and once again "You have no chlorine"
I was told you should only have to put conditioner in once but I am losing chlorine like crazy it seems.
They tell me w/o conditioner, I can't keep the chlorine from evaporating so I add in another jar and more shock, etc.
Salt pool. 20k gallons.
Salt cell is in good working order.