Use of fungicides, bactericides, soaps and compounds.

[Cdmcmonigle]

Has anyone heard of chlorhexidine for horticultural purposes? I was wanting to try it as a soap for my orchids. Also, I have used physan 20 recently on my plants, I bought thiomyl and dacinil to prevent resistance buildup. I am looking for any advice on using ANY fungicide or if anyone has used beneficial bacteria in their root zones with success. I grow mainly in a coco chip/LECA mix, some have sphag thrown in, a few phals are growing well in full water culture, and nine of them are in a hydroponic setup. I have two zygo's that a are currently in seclusion from fear that they havea fungus. Two cattleyas might also have a fungus. Any words of wisdom, what has or has not worked for you, regimes, preventitive strategies...