Thanks for all the replies
Tyler - I couldn't get anymore off without ripping off roots...the roots are essentially glued to the hydroton, and even with soaking maintain the rigid shape...basically the shape of the container.
I have also found that how successful
SH is depends critically on when you do the transplant....also, the other little lesson I learned is that once roots grow into the reservoir, they become 'water' roots and then if you let them dry out too long, they die. I just put a few more catt types into it, mainly because I despise watering, and this makes things ultra easy. I can even put the plants outside without worrying because as long as the little reservoir is not empty, I know my plants are moist enough.
Maybe I should have just ripped off the roots...it's growing new ones anyway!