FWIW, I have an eheim cannister on my system which has accumulated a couple inches of fine sand in the bottom of the media area. Still silent, still works perfect.

I have fine sand in my 27 nano and I find that the outside filters slow down a great deal if sand gets stirred up. I think your flow would eventually slow to just a drip over time. How will you clean the media bag/sock once it is plugged with silt? I think it might become a nightmare for you to maintain.

Thanks everyone for your input, and good point about maitenance. I suspect that you guys have saved me a lot of time and heartache. I am planning on getting three or four stomatella and two or three ceriths to work on keeping the cc substrate turned. Does any one know if ceriths will still dig through small crushed coral? Or do they only do that in sand?
Thanks again,

- Chad

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I'd say get a conch but the tank might be too small to support it. Also, I've seen people use a layer of fine screen under sand beds to keep the sand from falling through the bed filter if that helps.

Ya, to bad there's no such thing as a mini-conch. I had thought of using a fine screen under the sandbed but now I'm worried it might get plugged over time and require the sand bed to be dug up to be cleaned. ?
Thanks for your thoughts.

- Chad