This worked great for my 220 with 90 gallon sump. I'm getting an external one with an auto neck cleaner for my new setup. They sell for $799 new. Asking $600. Here is a link to one at BRS. http://www.bulkreefsupply.com/super-...n-skimmer.html Water depth is 6-10 inches with I think 6.5 as the optimum. I had mine on a stand to lift it up to 7 inches because I wanted a deeper depth in my skimmer compartment in the sump.