Hi Andrew-- Is the light filtering stuff the same as the diffusion panels known as egg crate? If so, this is the same stuff that many darters use to build their false bottoms for water features. I'm not a fan of egg crate, although I've used it. I don't think this is necessary unless you are planning a water fall, pump, etc. Otherwise, you can just go with a coarse gravel of Hyton (3" or so) layer topped with polyester padding such as is used for quilt padding for draining off excess water from misting or plant watering. Then put your substrate on top of this. If you want a pond for your Cresty, you can leave a section free from the drainage material, sink a bowl or water dish so that the edges are just above the substrate a bit, and perhaps plant some Java moss around the outer edge of this. I assume cresties drink water and also drag along substrate when they want to soak or drink, so you want a source you can change and keep fresh rather than something connected to a drainage area. If you just keep your plants damp without over-watering them, you will probably never have to sump out the drainage layer at all. I'm assuming that cresties require less humidity and probably don't like as wet a substrate as darts enjoy. As for the millipede, I'm not sure how prone they are to falling in water dishes and drowning. You might want to throw some Java moss in there and make a little ramp of some sort from water to shore just in case. You can just put the Java to one side when changing the water and use it over again. Not knowing dip about cresties, except yours is cute, I'm guessing a bit here. Hopefully someone keeping them in a living vivarium will have some suggestions.
Changing the subject a bit and asking a few questions back: Do you think the big tropical millipedes would get along with darts and tolerate the same humidity and wetter soils? I've seen some really pretty ones in the pet stores. The only millipedes I have are those that just show up, probably from the tropical plant nurseries. They are small, harmless and eat only detritus and such, so I rather like them. A lot of people freak out when they find them in their dart tanks, because they resemble centipedes superficially, but I find that over time, their populations bloom at first, then diminish to the point one rarely sees them. Do the larger ones climb glass? The smaller ones in my tanks don't seem to. Do you feed them anything special?
-----
Patty
Pahsimeroi, Idaho
Dendrobates: auratus blue, auratus Ancon Hill, tinctorius azureus, leucomelas. Phyllobates: vittatus, terribilis, lugubris. Epipedobates: anthonyi tricolor pasaje. Ranitomeya fantastica, imitator, reticulata. Adelphobates castaneoticus, galactonotus. Oophagia pumilio Bastimentos. (updated systematic nomenclature)
