Looking to ID Algae in Sump

[DKoKoMan]

I welcome all feedback It’s interesting how slime shows up in some tanks and not in others. Update... chaeto is still alive (slow growing as I haven’t noticed it any larger) and dosing 18ml vinegar. The slime has all retreated, the filters in between the baffles are not plugged and nitrates are still a little high. I’m going to continue to see if the slime returns with the sole use of vinegar as my carbon source.