upside-down sand bed????

[crew33]

I'm going to build a refugium and was wondering if anyone has tried the upside-down sand bed? What are your thoughts on this and is it truely beneficial? Any hints at how to build a successfull one and do you have pictures?

Thanks for your help.

[Entropy]

Not familiar with the upside down sandbed approach. Can you describe it?

[sylaak]

There's a plenum under the sand bed and instead of the water being sucked through the sand and up a stack, the water is pumped down the stacks into the space under the sand bed and forced up through it.

[jim.l]

That's an undergravel filter and was standard in the old days. It works, but not great IMO. If you do it, make sure you filter the water you're pumping under the plate or it won't last long.

[Steven Pro]

Originally posted by sylaak
There's a plenum under the sand bed and instead of the water being sucked through the sand and up a stack, the water is pumped down the stacks into the space under the sand bed and forced up through it. That sounds like a reverse flow undergravel filter. They are ok for biological filtration/nitrifying bacteria, but won't reduce nitrate and are unnecessary if you have enough liverock.

[Entropy]

I had that kind of a setup on my FW tank for a while, and the only advantage I can thing of is that it will keep detrius in the water column longer (hopefully to be sucked out by the overflow, or skimmer.

[crew33]

Thanks for all your feed back.

[Nuhtty]

There is an article in this years annual Marine and Reef Magazine about this.