sry for the lame question but what media is that? looks like rockwool but white? never seen that around here
It's STG (Sure-to-grow) Hail.
I would explain it like this, STG is to hydroton/rockwool like P.A.R. T5 lighting is to HID.
STG is non-wicking, inert, Ph neutral your roots will grow right through it. I had to get it online no local hydro store carries it, one of the guys told me they carried it a while back and people complained about salt build up, I bought "Drip Clean" by House & Garden to prevent this, the hydro store guy also said the locals where so use to using rockwool and hydroton that it's hard to get them to buy into a new product... since this is my first go at hydro I figured why not try it out!
So far I really like using it, I've cloned from cuttings in it, it is super fast to pot a net cup, they say it's reusable but I would only reuse the stuff on the top and throw away what the roots have worked themselves through.
It cost's the same or less than rockwool. Rockwool is actually hazardous to humans that's why they wrap it in plastic and should only be handled wet.
You should give it a try, STG also comes in blocks, mats and any size net pot insert you currently use. They have a 1/2 off sale on the Hail product.... I'd also like to try their tornado inset for the 6"x4.75" net pots.
[video=youtube;EKzqa8X4qOo]http://www.youtube.com/watch?v=EKzqa8X4qOo[/video]
[video=youtube;pmOmViRxbgY]http://www.youtube.com/watch?v=pmOmViRxbgY&feature=related[/video]
[video=youtube;wDwG4qbqhKc]http://www.youtube.com/watch?v=wDwG4qbqhKc&feature=related[/video]
Happy growing
UCDWC~