I’ve been quite happy with the low maintenance filtration solution I implemented for my 33L.  Two AC70’s with AC30 impellers, dual sponges and extra biomax have provided a stable, huge mechanical and bio-filtration system for my display shelly tank.  My main concern is the oily slick left behind on the surface from their NLS Cichlid Formula diet.  It’s unsightly, and I wanted to eliminate it.  I turned to surface skimmers as a potential solution.

After being disappointed with the Fluval / Hagen surface skimmer attachment (bluky, unsightly, awkward to deal with on a custom background), my search for a surface skimmer for my pair of AC70’s turned to DIY options.  I came across the following thread that had a great, cheap, DIY idea based on a few pieces of 3/4″ PVC “T” and elbow joints.  I added a 3/4″ pipe to the list for joins, but the basic concept is pictured here:

http://www.nano-reef.com/forums/index.php?showtopic=238562

My customizations focused on a 1″ long insert to join the “T” and the elbow, and a Filter Max III prefilter that I use as a standard piece of equipment on my stock AC70’s.  These prefilters keep out plant matter and fry while acting as a good mechanical filter to my AC70’s.  Here’s an image of my final customization with the Filter Max’s siliconed in place with a reducer fitting from the kit inserted into the “T” (this was necessary to minimize the overall height of the solution to fit in my 12″ tall 33L):

	The initial plumbing consisted of a stock AC70 return, a 1″ PVC T joint, elbow, and small 1″ pipe used as a joiner for the T and elbow. The tip of the AC70 return was cut off and inserted into the elbow forming the entry point of the skimmer. All white surfaces were spray painted flat black.
	This is a top down view of the T joint showing how the stock Filter Max III plastic fitting was inserted into the base of the T joint. Silicone was used to hold it in place, though the Silicone did not bind well to the surfaces. The Silicone provided enough of a friction joint that the Filter Max’s generally stay in place.
	As seen here, the tip of the filter cage was sawn off to make a shorter skimmer stack. Note this skimmer does not “float” or adjust to changing water surface height, so the cage needs to be tall enough to manage changing water levels specific to the tank it is being inserted into. This photo also shows how the main AC70 elbow return is fitted into the top of the T allowing for the skimmer to be attached to the AC70.
	Here is a close up view of the skimmer unit with the reduced skimmer cage in place. The fittings on both ends of the T joint are in place.
	A top view of the skimmer unit.