Mechanical filter with chaeto?

How would you light it?

Are you running without a sump? If so I have seen tanks where they just stick a ball of it behind some rocks mostly out of sight so that the display lights provide light. I wouldn't think you could get very much chaeto in a hob filter. What kind of tank is it?

You've come up with a great idea. It works good and many others have had success with it.

I don't have a hob filter for my tank yet. I was checking my filter on my little freshwater tank and thought that maybe that could work as a mini-fuge on my salt. I know a lot of people use chaeto in their fuges, so I figured this is pretty similar idea. Would the AquaClear 50 be suitable for my 30 gal? Maybe I'll get to work on this fairly soon. The only problem is lighting.

I believe they call them "power filters".  I have a TopFin 60 on my 29 Gallon.  I was trying to set it up on a budget so I used that instead of a refugium or sump.  There are little slots to stick filter pads in it, but I use it strictly for biological filtration, not mechanical.  It comes with a little removable lid, which I took off so I could light it.  I found one of those little cheap power compact lights that clamp onto the edge of a tank and put that over it.  I put it on the same timer as my main display lighting.  I put some live rock rubble, coral skeletons, etc. in it as a biological filter and then just wedged the chaeto in between a couple pieces of rock.  This all seems pretty ghetto and incapable of supporting livestock, but it is fine so far with four fish and some frogspawn in it.  I test the water regularly, and the nitrite/ammonia are undetectable.  The nitrates have remained low, and the chaeto is growing, so I think it's doing it's job.  Just remember, if it has one of those little uptake pipes that stick down into your tank, put a slotted cover over the end.  I forgot to use the little slotted cover that was provided with the filter, and I got home to find the filter making an awful grinding noise.  After removing the impeller, I found my midas blenny decapitated in the impeller area.

I can definitely get you some pictures of it.  I go to school in Logan, but will be in Salt Lake (where the tank is located) over the holiday weekend.  I will put some pictures of it on here on Friday when I get home.

I don't want to bag on anyone's ideas (they're good ideas, after all), but in my 37 I just stuffed some chaeto behind some rocks.  It looks a little funny if you know what to look for, but it's not immediately apparent or anything.  The tank still looks good.  

That looks awesome James. How are your params after you installed this nifty device? I really like this set up. I want to get started on this if there is a worthwhile effect on the params. What kind of power filter is that?

They are basically pond lights.  I got mine off ebay and it is a focused, narrow light.  You'll want to search for a 10 watt halogen light (or two connected 5 watt lights).  It was about $18 (shipping included).   It seems to be working fine (I've only had it running for the last week).  You can also get one from here which is not as focused a light (and actually preferable in my opinion):  http://shop.mediabaskets.com/DOUBLE-Underwater-Light-DOUBLEQL02.htm - this guy sells stuff specifically for nanos.  He's very active on nanoreef.com.   Here's a thread specifically re: the lights he sells (which you can find from other vendors, just like I did on ebay):  http://www.nano-reef.com/forums/index.php?s=5a561d3faab87bc3d3d61d0556032496&showtopic=194713&st=20 .  It does indicate that the halogens will not grow chaeto as quickly as a regular clip daylight bulb would, but lead to constant growth.  I've got my chaeto split between the fuge and display right now and both seem to be doing fine.  Here's a pic of my setup w/ the light: