I was using a SCWD, and had to take it off the system and clean it out twice, to get it working again (algae/sand jammed in it). I knew it was sapping flow, but no idea how much. I swapped in a more powerful return pump and saw very little difference. Then I bought an Oceans Motions Squirt and the overflow can barely keep up with the flow (I'll have to put my smaller pump back on!). It rules. However some things to consider;
- SCWD is cheaper $30-$30 than Squirt
- SCWD restricts flow, so it actually robs value from your return pump (wasted power, etc)
- SCWD rquires no power of it's own....but in effect it's using power from the return pump
- Squirt is more expensive $100+
- It takes power to run
- It doesn't sap flow from the return pump any more than a 90 elbow (I'm totally guessing)
Both seem well made. I think the Squirt might be more user servicable, as the SCWD is sealed and you have to get lucky to get one working again if it jams.
My opinion, anyway...if you can afford it, get the Squirt and pass on the scwd.
V