I have a 2,000 gallon pool and filled it with well water. The only time I can get it clear is when I add the "green to blue" chemicals which then the pool is clear but has brown cloudiness at the bottom. I thought I could get a sweeper to sweep it out but it just goes right through the vacuum and makes my pool brown and cloudy again. It’s not particles so it will not sweep up, just cloudniness sitting at the bottom of the pool till someone gets in a stirs it up again. I’ve tried everything!!!
It sounds like it is probably a small amount of metal from your fill water. You can add a dose of metal treatment/remover to get rid of the brown cloudiness.