signs of under powered skimmer?
 

what are the signs my skimmer is under powered?

when your bank increase the credit limit on the card.....

if there's a '9002' stamped on it anywhere.

If your skimmer pulls a lot of gunk out but you still have high nitrate and or phosphate or lots of problem algae/slime it might be a good skimmer but too small for your bioload.

I'm gonna say when it's not plugged in :)

well i got this oil slick crap on the top of my water and even though it keeps going down the overflow it still sticks around. I was thinking maybe the skimmer wasnt pulling enough crap out of the water.

Try aiming a powerhead towards the top create a rippletowards your overflow I always keep lots f surface movement for that reason:)

one of my tunze 6105s is pointed at the top and my return is at the top. so lots of surface ripple

whats your tank turnover rate?

I had the same issue on my 225. Even with a pair of 6100s aimed slighlty towards the top there were 2 corners that always stayed a safe haven for the oil slick.