Hi;

I recently built an interesting sump/refugium. I don't have any pictures, but I'll try to describe it. It's made out of 1/4" acrylic. I used extruded, before i learned that cast acrylic is much better for any project that's got to hold a lot of water, like more than a gallon.

It's a rectangle, about 30" by 14" by 14" deep. Larger would work better, but that's all I could fit in my stand. Basically, there are 3 sections: on the right, a 4" section to catch the drain from the tank, a 12" middle section to hold the skimmer and fit the outlet bulkhead, and a 14" section on the left that's a refugium. I teed off the drain with the 1X1X 1/2" side outlet elbow. The 1/2" outlet holds a ball valve which regulates flow to the refugium. The refugium drains into the center section through a 3/4" bulkhead high in the divider between the refugium and the center section. There's a bubble trap, basically an under/over set of baffles, separating the right (drain) section from the center section. Low in the left corner of the center section, I drilled for a 1" bulkhead that attaches to my return pump.

The idea is that water from the tank and the refugium both drain into the center from either side. This way you can send some tank water directly to the refugium, and water from the refugium doesn't get skimmed; it drains close to the return pump outlet. You don't need any supplemental powerhead to feed the refugium, and in a power outage or return pump failure, the refugium stays full. Most of the micro bubbles are caught by the baffles between the right and center sections, and I improved it by putting an elbow inside the outlet bulkhead, facing down, so that the return pump draws water from very low in the sump.

It's working well, and I think it's a good simple way to have separate flow rates for the main sump and refugium. Plus, you're not sending skimmed water to the refugium or subjecting the refugium to the chemical changes that ocurr in a sump when you dose KW or other supplements.

As far as a class sump/refugium goes, I've had bad luck with siliconing acrylic to glass. Other folks have had no problems, but for me, a good acrylic sump is the way to go.

Matt