I just use plain tap water in the machine. No special liquids required. The Clonex gel goes a long way and does help speed the process up. You can also make these devices cheaply with plastic totes from Wal-Mart, etc. If a cutting is more difficult to propagate, I dip the cutting in the gel every other day for about a week. I turn the machine off and let the gel sit on the cuttings for about 10-15 minutes. The plants don't wilt either with this machine. Another nice thing about it is I can go on vacation and come back and all my cuttings are rooted. I'm just doing this for fun, but I can see clearly how this machine could pay for itself rather quickly.
Here are some instructions for making one:
http://seventhstreetcottage.bl...
http://growhousebuilders.com/b...
