Well, I guess to answer both of you guys, the answer is NO I did not re-use the Hydroton from the first growth. Its new, and rinsed.

However, I am sure one day I will need to wash it, so if not bleach, then what?

Also, if I have build up NOW, what should I do to get rid of it? And how often do you need to rinse the media when growing? Like I said its only been about 13 days and I saw problems at around day 9 or 10. All new growth seems fine other than the fact it is slow as can be.

The only thing I DID re-use from the first growth was the net pots.
And two of the buckets. But the two that I re-used does not seem to be a reflection of a problem at all.

I really need to get that book tomorrow or something!