Hi,

I'm quite new to both bonsai and hydroponics, but I've been keeping a
couple Ficus, Willow, and Serissa alive for a few months in an ebb and
flow setup using lava rock gravel as the medium and supplemental
fluorescent lighting.

I change the water about once a month, but recently I've noticed a
problem. A fine white fluffy mold has started growing on the roots and
leaves. This is really perplexing me, because I spray each plant with
a fungicide every few weeks. The specific brand I'm using is
"Fungicide 3" by Garden Safe, a pesticide/fungicide mix. I lost my
first bonsai, a juniper, to a combination of spider mites and
insufficient of light, so I've been keeping a much closer eye on my
current bonsai.

So far, the plants aren't show any signs of distress, but I've only
just noticed the problem. How concerned should I be about the mold? If
it's harmful, what would be the best way to get rid of it and stop it
from returning?

Thanks,
Chris