I'm getting ready to setup a 75gal tank. I going to use 2 Emperor 400. Would I need to use a protiem skimmer. I'm going to have a non aggressive tank with cleaners.
Unless you are planning on setting up a reef tank, i don't think it is absolutely neccessary to get a protein skimmer. However, it will only be to your benefit to have one, it helps to get rid of waste in the water that can't be filtered out otherwise, also helps to control and keep your nitrates down.
But...it is a very good idea to let the tank to mature for about 4 month before even considering to get a skimmer. In not matured tank.....it very difficult (i would almost say impossible) to adjust it right and to even get it to skim anything.
I do not find this to be the case at all.
I see no reason to wait- as soon as you are feeding and fish are producing waste a skimmer will produce skimmate.
I only have live rock in my tank, still cycling, and im getting a small amount of scumm produced, some of it gets into the collection chanber, but a lot collects around the throat, i just clean it every couple of days.