I was looking into other options for switching flow and found this
http://www.reefonline.com.au/shop/pr...roducts_id=150 on the SCWD. The times seem a bit high from what I remember, though, but I never did actual timing tests. Maybe I'll do a few tests of my own.
I used one with a Iwaki 30 series pressure pump on a 75 and loved it. People talk about them breaking and being crappy. Near as I could find, those people were jamming alot of water through one which I don't think it's engineered to handle. It's quiet. No electronics. Cheap.
I fully plan to re-use it on my 37 when I get it up and running.