Hydroton is pretty easy to identify if you've seen it before. It's a reddish brown on the outside, black on the inside (not hard to crack one open if you want to) and is really light for its size. It's like the rock version of popcorn.

I'm intrigued by this notion of SOG nutrients, though.

I'm not sure exactly how specialized the nutrient requirements would be in SOG but there are a few things that would benefit that style of growing more than others. I use Advanced Nutrients since it seems the most versatile to me, I wonder if I could tweak my mix somehow.
hugetom80s Reviewed by hugetom80s on . SOG! :jointsmile:I have an 8x4ft table, (flood and drain) . 3-600w hps, 127 pots, (or so). 115 gallon res. One part nutrient (dutchmaster) . lights have digital ballasts with glass shielded light. My clones will not be topped (using ww strain) and they will be under 18/6 during short term veg maybe 2-3wks. Flowering will be 12/12 for 9wks. If anyone has done a large to moderate size S.O.G setup then please feel free to give advice on my future grow. Rating: 5