I've seen some pictures of people's plants on this site and it looks like they're growing them in brown rocks? Whats the exact name of these "rocks?" and also is a 400hps to much power for just two plants?
they are known as Lava Rocks and are used in DWC (deep water culture) cultivation... you cant grow in JUST the rocks, its the water thats the key part 400hps will yield quite a bit with 2 plants... the more light the better
Mentally I think of the stuff as cocoa-puffs, but it's actually called hydroton. Hydroton Derived from a renewable and plentiful source (clay), Hydroton is considered an ecologically sustainable growing medium. The clay is formed into pellets and fired in rotary kilns at 1200C. This causes the clay to expand, like popcorn, and become porous. Hydroton hydroponic growing media is light in weight, does not compact and is completely reusable - it can be cleaned and sterilised after use. They are also inert, pH neutral and do not contain any nutrients. The pellets drain freely and do not hold any excessive water, which is why they provide good oxygen levels around the root and why they are particularly suitable for flood and drain systems. In drip irrigation systems the pellets can be mixed with a medium with better capillary action so the feed is dissipated broadly through to prevent salt build-up. Hydroton hydroponic growing media is a substitute for normal plant-soil and is mainly used in hydroculture / hydroponic systems as well as for decoration. http://www.planetnatural.com/site/hydroton-grow-media.html