Step 4 - Growing Medium:

   According to my research info, the best mesia for a reservoir-type system are Volcanic lava Chips, or a 1-part Vermiculite/5-parts Expanded Clay Pellets mixture. I couldn't find Lava Chips, or the Clay Pellets in my area, so originally I opted for Vermiculite and 'Ground' Clay (at a 3 to 1 mixture), but the Ground Clay holds too much moisture. I've switched to a 50/50 mixture of Vermiculite and Perlite (see photo 5).

Hydro system photo 5

   Whatever media is used, it should drain well and be firm enough to give roots a strong support to hold onto, yet light enough that it doesn't compact tightly when moist and prevent roots from growing deep or getting air and nutrient solution.