Somehow the topic changed quite dramatically, apparantly we are on a completely different subject now, maybe
khsheh can repost his experience and sharing in another new post, I am sure this will attrach more respond then hidding inside a post with a different heading.
Back to the original question, I suggest you go for lighting that has a plastic or glass shiled, and then replace the top plate with a smaller one, let the lighting device do their job and can shide upon the wate as they should have. There is no need to worry about dust entering the tank normally, unless you placed your aquarium at an extraordinary place. Condensation happens, but once you use the light to cover up part of the tank top, it will stop condensation to certain extend level anyway.
