1) Those are botanicare hyrdoponic grow beds. but i dont recommend them. They are expensive and shallow 4"-6". They work obviously but you are limited to short plants greens and herbs. Tall plants will have a problem staying upright when the wind blows. I try to make my grow beds 12" deep.
2) You can get premade grow beds like those at a hydroponics supply place
3) Other grow bed options inclide wood and pond liner, food grade barrels or ibcs cut in half, anything that can support the substrate, holds water and wont leech.
4) I use 1/2" expanded shale. It's a little bit lighter than river rock and porous. It is not PH nuetral. It's relatively cheap when you buy it by the CY. River rock is a good just heavier.
You may find alternatives rocks thatw ill work well. Anything that is ph neutral, and .5-1" in diameter should work well. You can test media ph by submerging it in vinegar. If it is a alkaline you will see bubbles.
I try to avoid pea sized gravel because it has a tendency to clog up with fish solids and plant roots.
The expanded clay balls you get at the hydro store are light, ph neutral and pretty perfect, but they are about 14x more expensive, If you are doing a very small system it may be worth it because you dont have to buy in bulk.
