I'm building a 29 gallon terrarium to be used as a model of the water cycle. It has a heated pool area and a sloped lid, cooled to encourage condensation and allow rain to fall over the land side. Everything works great, except the front glass is getting too foggy. Has anyone ever tried any of the anti-fog coatings sold for scuba masks? Does anyone know if they'd be safe to use around plants. At the moment I'm not planning on adding animals so plant toxicity is my biggest concern. The company that makes them claims they're non-toxic and biodegradable, but so far they won't tell me how quickly they break down. Any advice would be appreciated.