I just buy the black aquarium silicone online. Yah it's not going to be cheap, nothing is these days, but at least I know it's safe. The DanConnor's suggestion of the LED spot lights was a good one. I use the exact same ones in one of my paludariums (no dart frogs) and they punch all the way down to the bottom. 4 feet high in total. Maybe you could put a strip across the top as well. I use both AquaticLife Edge and Fluval Plant Spectrum LED strips. They both throw off a little heat but up, not down.Suggestions on the brown / bronze?