The Orca in my opinion is s**t , i wish i would've shopped around for another nano but in haste i ordered it, anyways my skimmer is a joke i have tried everything to get it working ( without success)& to boot my heater broke within a week so i had to replace it , my U.V however does seem to be working because the red light is on ( im only guessing it works but i could be wrong )
if i was you mate i would return the tank and ask for your money back & maybe find something that is half decent & hope you find a tank with instructions on how to use it & working parts .
I agree that the skimmer on the orca is rubbish but the system itself functions rather well. I've never had any mechanical problems with the heater, lighting, or stock pump.
Apparently, to use the skimmer on the orca, you have to set your water level pretty low... i dont like doing that, i dont want to see the surface through the glass.
I took the skimmer box out and run it with skimmer off.
Take out the factory sponge, put a poly filter against the inlet vents and stuff filter wool behind the poly filter. Use some seachem puigen in a seachem "the bag" in the last filter compartment and you'll have everything you need to be pretty much skimmer-less with the orca... change a bucket of water once a week.
The reason i chose a orca, I watched thread after thread and have seen some super tanks especially cmw328i very insparational and stone cold's both highly admired. I believe as long as i take time then nano reef can be achieved to very high standards even within the orca.
My first intention was to use live sand but lfs said "I dont belive in it, how can sand be live after being collected, conditioned, packaged and stored for any period of time" so i purchased from him 2 bag's of argonite coral sand. I will seed the tank with live rock for 6 week's (going on holiday) so hopefully my sand will become live!!!!