I have a 90 gal with a 30 gal plumbed together i stopped using my skimmer before i set up the algae scrubber was reading a lot on them for a while and watching other tanks that have them my skimmer never worked right for more than 20 mins anyway i have NO SKIMMER on my tank only do a 2-5 gallon water change every week and dose a lil calcium strontium iodide in the 90 i have 22 fish all on the small side the tangs are the biggest in the 30 gal i have 12 fish i feed heavy 3 times a day also all kinds of coral and a lt nem and my tanks are great all in check temp is 80 1.024 2 250 mh lights 0 nitrates 0nitrites so if skimmers are a MUST HAVE why does my set up work without one??? ???oh and another MYTH i feel is ro di i use STRAIGHT TAP WATER but thats for another post