I'm thinking it's dead algae.
Keep an eye on your CC's and maybe do another OCLT just to confirm there's no organics.
You can vacuum to waste if you like. If it's dead algae it's no problem in the filter.
Keep an eye on your CC's and maybe do another OCLT just to confirm there's no organics.
You can vacuum to waste if you like. If it's dead algae it's no problem in the filter.