Hi there we have a 1/2 acre pond with a liner

It’s about12 feet deep in the middle and 4 feet all the way around. It was built for swimming but it’s not clear . It has no outlets so it’s just stagnant. We have a fountain and one aerator it’s not clear like it was when we filled it 3 years ago. Wondering if there’s anything we can put in it to make it clear and rash free? Is there any type of chemical we can put in that would do wonders? Frogs love it but the kids tho
K it’s gross. It’s just an eyesore although it’s no nice to look at. We have thrown in pond clear from the pond guy and do throw a few in every couple of weeks. We actually drained hall the water and cleaned it last year after a couple kids got a rash from swimming in it


Thanks