It could be dirt from the environment, it could be dead algae, it could be sand from the filter. Here is what you do to "test" for each one:
-dirt-it is what it is. Nothing you can do about it
-dead algae-have you done a OCLT yet? Pool School - Perform the Overnight FC Loss Test (OCLT)
-sand-have you opened up your filter and looked inside it? How about a deep clean? You can put a fine mesh bag or sock over your return and see what comes out.
Kim:cat:
-dirt-it is what it is. Nothing you can do about it
-dead algae-have you done a OCLT yet? Pool School - Perform the Overnight FC Loss Test (OCLT)
-sand-have you opened up your filter and looked inside it? How about a deep clean? You can put a fine mesh bag or sock over your return and see what comes out.
Kim:cat: