We have a 20,000 gallon liner pool with a DE filter. We have been opening it to pea soup green for the last 4-5 years. Have used large amounts of liquid chlorine to clean it up.
This year after getting it clean and chemistry balanced, the chlorine level dropped to below 1, not all the way to zero. We could not bring it back up with the pool chlorinator on full. It was suggested we check for phosphates.
Phosphates were off scale at over 2500 ppb. We fought this for weeks and got things back to balance, using dichlor as well, but phosphates are still over 1000 ppb.
Have you had this experience and did phosphates contribute to the problem? How do you control phosphates? We have had this pool for 17 years and the last 4 years have been difficult on opening. We live in Ohio Removing phosphates really mess up our DE filter.
With any sanitizing system you will still likely need to shock the pool when the chlorine gets “locked” on to algae. 2 -3 gallons of liquid chlorine 1x/week should help on a regular basis. We have found that we don’t need to treat for phosphates separately when people keep up on the weekly shock – which we do with all of our weekly service customers whether they are on salt/chlorine generators or tablets.
Are your grids getting acid cleaned regularly?