Oh it’s stupidity that turn the water green.

The decomposing shit in the filtration system from being turned off for weeks released free ammonia when they turned it back on. This triggered a massive algae bloom.

It was easily preventable by flushing the system before they turned it back on.

In order to fix it they need to clear out all the detritus in the pool and add a flocculent. It should then clear up in around a week.

In order to keep it green all summer, it needs a little help.