I used lava rock and perlite in this tower. The solar pump kit was on ebay for $15. http://www.ebay.com/itm/Solar-Water-Pump-Power-Panel-Kit-Fountain-Pool-Garden-Pond-Submersible-Watering-/120956047067?pt=LH_DefaultDomain_0&hash=item1c298acedb
I have tried different ones and this is the best of them. I filled a sock with compost and placed it on top where the water flows. I use 1 tsp of nutrients in the 5 gallon reservoir that I change weekly. I mix 4 parts miracle gro for tomatoes 1 part Epsom salt and 1 part calcium nitrate to make my nutrients.