Hey,
If anyone reading this has made any "adjustments" to their skilter filter to make it more efficient, quieter, or just ANYTHING, please let me know what and how to do it.
I've had one running on my 20 gal for almost 3 years. I use the method described by AnemoneBuff, and with a good, as in a large, air pump, it works quite nicely. When the wood eventually breaks down, and bubble size/count fall off, I also emply JohnD's method with the longer intake hose on the venturi. If you like to produce the light green skimmate that some folks prefer, it's quite easy to fine tune your gunk output with this combination. I used to do both all the time, but found that the 400 skilter set up this way pulled too much water out of the system and with evap. losses, I felt I was putting the animals at risk with fluctuating salinity.
Whatever you do, don't try and run these units on a tank anywhere near their stated capacity. The 400 is supposedly rated for a 100, but I feel it wouldn't be wise to run it on anything bigger than 40 gal. for it to be effective.