This is a simple sponge filter for breeding and larval tanks.It requires two zip ties, a porous filtration sponge from your local fish store, some airline, and an air pump.Assembly is pretty simple. Print this out, attach an airline, wrap the standpipe with the porous sponge and zip ties, and attach the air pump. Done.For those of you unfamiliar with sponge filters, please see the following URL: http://www.jehmco.com/html/hydro-sponge_filters.htmlThe scad file is attached in case there are changes that you'd like to make. Assembly photos are attached as well. Print and enjoy!Depending on your local fish store (LFS), you may be able to find cylindrical or block sponges with the appropriate diameter pre-made in them. If not, you can either get a flat sponge and zip tie it around the filter stand pipe or bore out a 20 mm hole in one yourself.Feedback is welcome on how to make this better for everyone.