Pool is about 18k gallons so it is not a big pool. Gunite and plaster pool. I have to figure out how large of a filter I have. As for the algae I think most is dead now. but what is there is greenish brown and looks kind of like diarrhea, when you try to scim it off with a net it breaks off into pieces and goes right through the net.

As for a test I have yet to do one yet.