I just got an Eshopps 75 HOB for my 40 gallon. A little smaller and cheaper than the RO-90 I was considering. I love it so far. no complaints from the wife about noice or being an eyesore, and pulls good skimmate after just a day, so it's a winner in my book so far. Slight leak when I got it, a bitof 2 part epoxy fixed that in about 10 minutes though. I'd either gofor the Eshopps or RO-90