I have $240 in my system including a Gast 523 pump and dual 9" diffuser discs. It has been on constantly for almost a year with no problems. I "messed around" building my own because I believe my mind is as sharp as anyones when it comes to all things mechanical, and I don't see the need to pay others to do the rudimentary wiring and plumbing required to build a simple system. I'm not slighting anyone for selling them, but don't tell a guy who obviously has a DIY streak he is wasting time or he will save money by paying more up front. He will just laugh at you.
