Mosquito Bits Okay?

[Sitka]

Hi All

I have some of my orchids here at home and several at my office. My co-worker has a bunch of plants in the office as well. We have noticed recently a lot of fungus gnats floating around. I am looking for something natural and harmless to my orchids that I can also use on the other plants to get rid of these annoying little boogers . I have looked on some orchid supply sites and they have mosquito bits and mosquito dunks available. I was wondering if anyone has used them? and/Or would you recommend them? They contain a natural bacteria that kills the larvae called BTI? Thanks for your time.

Sitka