Bobull: There's always another way of doing it. If you're not trying for a high volume crop many of you might consider this. I use a starter tray with a two foot T-5 light rack over it for cloning. I like it because it's so simple.
I treat my rock wool cubes, make my final cut under water, immediately dip my cuttings in Technaflora's cutting gel and stick them in the holes I made in the cubes with a skinny bamboo bar-b-cue skewer. I run the lights on them 18 on and 6 off.
My cloning system is a combination of three trays and a dome. The bottom one is your standard black plastic tray about three inches deep. The second one fits neatly inside the first one and it has a coarse plastic screen bottom that roots can get through. The top one has fifty squares with drainage holes at the bottom for cloning or starting seeds. It's all topped off with a large humidity dome with adjustable vents. I think the whole things cost me about twenty bucks, if that much, and it makes a lot more than I can use.
The cuttings are already saturated so I just fill the nutrient level to the screened bottom of the middle tray and cover it with the humidity dome. I use Technaflora's cutting and seedling formula and I change it about every week or so. I foliar feed my babies two to three times a day and I've had about a 75% success rate. I was happy with that but my friends at the hydro store said if I could improve my average if I used a heat mat. I bought one and next time around I'll try it. I haven't added an air pump because so far I haven't felt the need for it.