For starters what ever product you use it won't effect your animals in your tank as long as you are not staining the canopy on your tank!
Salt will be your first enemy to your stand and canopy, With lighting and if you use fans to cool your hood mold should not be a problem here.
use a good rubbing stain on the wood but first apply a sealer on the pine if you want a uniform look, pine can and will stain blotchy due to the softness of the wood. I prefir a pre catalysed magnelac lacquer for a finish, spray this as it dries very fast in a well ventilated area outside. brian