Let’s fly all over the place here,
First, it’s very common for a pool to turn cloudy after adding phosphate removers. The lanthanum binds to the phosphates in the water and depending on the levels can cause a pool to go cloudy. Normally they filter out in 2-3 days. At times you can even see this reaction occurring as seen in this video.......but please be warned, somebody needs to learn how to hold a camera ?
Next however, I wouldn’t rule out algae growing in your water and what you’re looking at is a start of a bloom. Do you have any test kit at all we can get some test results from?
Let’s say it is an indicator of an algae bloom starting, what’s the easiest way to nip it in the butt right this moment and a guestimate of how long that will take