While searching for something else I stumbled across this thread, and had a question.
With the clay aggragate top dressing are you getting moss growing on it? Provided you have high enough humidity to grow the moss. I'm still looking for a good way to not grow moss .
I set up a larger version of this about the same time, although I'm not using any nutrients. So far I'm having no problems growing any of the CPs in there like this.
Back to my searching.