Thanks for the suggestion. I'll give it a try!

I've undoubted created some of the problem myself by (1) using white
humidity trays which show every bit of crud, and (2) flooding the pots
in situ, which causes an unsavory mix of things to come out of the
drain holes: S/H particulate matter, decayed root sludge from orchids
recently potted in S/H, algae in the S/H pots, and decomposing bark in
bark-based media. That combines with drowned gnats in the humidity
trays to create an less-than-wonderful appearance. (I run three fans
and use sticky traps, but I still have some gnats.)


In article , Ray
wrote:

DD,

Add a little Physan to your tray water and you'll never have an algae
problem.