ive been looking at the oceanmotions diverters as well... gotta convince myself to pony up the $$$ for the diverter and the pump to go with it.
as for the SCWD, i believe is is a mechanical diverter in the body that switches the flow between the two outlets. since it relies on the water flow to move the diverter mechanism, you will lose flow energy, and ultimately reduce your flowrate through the device.
DIY stand and Hood,
Coralife Lunar Aqualight (4x65W),
60 LB Hirocks Base Rock, 40 LB LR 50/50 Keys/Gulf
150 LB Playsand (~3-4 in DSB)
2 x Blood Red Fire Shrimp, 2 x Cleaner Shrimp
2 x Black and White Percula Clown, 1 x Orange Spotted Blenny, 1 x Red Stripe High Fin Goby
The ocean motion has its own separately powered mechanism to control the different flows. The one you are talking about will work just be aware they will not handle much flow and will create a lot of back pressure on your pump.
*The fact that no one understands you doesn't make you an artist.
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I'm not sure exactly how a SCWD works, but I can say it does what it claims to. I've been using one for a few weeks now and love it. It does restrict flow some, but a proper pump will fix that and you can keep all that extra "crap" out of the tank. You can't beat a SCWD $ for $ IMO. There is a video of one in action on this site if your interested- http://www.melevsreef.com/closedloop.html