How does a SCWD work?

[jmack]

I am setting up a closed loop system for my tank (it's not drilled). How do the SCWDs work? Are they outside the tank? Where are they connected?

 

[snulma1]

Yes, SCWD are outside the tank, and they are usually hooked up between your 2 returns to the tank.

 

[chopsuey]

Here is some info on the SCWD and a pic:

SCWD Website

 

[jmack]

Thank you!!!

 

[Beach Native]

Actually you can run them enternal or external, makes no difference. My closed loop is almost exactly like the one pictured although I use tubing so have less elbows.

I actually have two of them running on my system and they both have gone over 2 years without problems. I had one freeze up recently but it soaked clean with a little vinegar and is back in action. Considering how little maintenance I have given them they have held up pretty well.

Everyone swears they kill flow, but I think for the price, they are nice little device.

 

[567a]

How does a scwd work?

It's all explained in this thread http://reefcentral.com/forums/showthread.php?s=&threadid=845649

but if you're too lazy to read it the answer is fairies.