"scum" in center chamber of sump

ive got a film on the top of my water in the middle chamber of my sump. should i add a small powerhead to that area?

 

im running probably 200 gph. its empty npw but id like to find a small skimmer for 30 or less gallons. its a drilled 12g aquapod with 10g sump

 

lookin to find a cheap one to try. small insump for 30 or less gallons

 

small update, i turned on my uv sterilizer and the scum mostly went away!

 

for the price of it that i found i can get a reef octopus. arent they supposed to be the bees knees?