Protien skimmer

I have a 40 gallon reef tank with 40 pounds live rock and live sand. I'm not sure the protein skimmer I have is working it's a redhead prize I got from a friend . I don't see any foam or separate although it also puts me to bubbles into my tank. I'm looking to buy a new one any recommendations? I've been looking at an octopus brand but would like opinions please