I saw that ya'll were talking about using coco as a medium. Specifically with the ebb n grow....
We use coco chips in both tables and ebb n grow buckets. It is reusable and retains a very good amount of moisture inside the chips that the roots can get at but drains very fast. You can't overwater with this stuff. We haven't run into any cal/mag issues while using it. It is also extremely inexpensive.
For cleaning between cycles we run some enzyme through it.
It comes dry and compressed. A small package, which is about a cubic foot and will expand out into about 8 cubic feet. The cubic foot package costs about 10 bucks.
Preparation is similar to hydroton in that it needs to be rinsed. We fill a bathtub about halfway with water @ 5.8. Add about 150 ml of cal/mag and a bit of thrive alive for the pre/soak rinse. Your first week of use the res is gonna get dark in color with little particles but it's np for plants or pumps. After that you don't get much in the way of particles and much less than you have using hydroton.
My favorite part of this medium is the fact you don't ever have to adjust your ph... even with AN my PH sits perfect for nearly the entire grow. Only time PH needs to be adjusted is during aggressive veg. growth due to release of n3.
It's a great medium and imo superior to just about anything out there except maybe Mapito which you can't get in the states anyway.
Anyway, nice grow m8 and here's linky to some coco chips.
http://www.sensivcocopeat.com/coco-chips.html