Here is what I tried typing before it got deleted:
First, regarding impaction from eating substrate - reported instances of this occurring are very rare. I wouldn't worry too much about it. There was some discussion about this during one of the
Chameleon Breeder Podcasts and they stated, even if your chameleon accidentally ingests some substrate, the chances of it causing impaction are quite low. You can reduce the risk by making sure there are no pieces of bark or large chunks of sphagnum moss on the surface. If you decide to go bio-active, your substrate should be covered with a good blanket of leaf litter anyway, so it renders a lot these issues moot.
Regarding removal of water which may accumulate in your drainage layer over time, you have basically 2 options: 1). drill a hole in your glass or 2) insert a PVC pipe to your drainage layer which you can use to periodically siphon water. There is a detailed post in
this thread by
@GoodKarma19 which outlines the process in detail. Whether or not you will need to siphon water out occasionally depends on your misting schedule, number of misting nozzles and your enclosure dimensions, specifically the length and width. If it is "skinny" and tall, obviously water will rise more quickly. I have both a 24x18x36 and 36x18x36 glass enclosures and the 24x18 (LxW) occasionally needs to have water removed. I have not yet had more than a few millimeters of water accumulate at the bottom of my 36x18. This is because it takes more water for the level to rise and because I have a higher volume of substrate and also more plants (due to larger area for plants) in the 36x18.
Regarding your misting schedule - 3 minutes twice per day should be fine. I mist 3 times per day but the total duration is shorter (5 minutes). 2 minutes in the morning, 2 minutes just before lights out, and 1 minute midday. Keep in mind, even if your total duration was shorter, the longer the duration of a single misting session, the greater the chance more water will seep to the bottom.
Regarding bio-active setup, there is a good blog post by
@cyberlocc which contains all the information you need. You can find it here:
https://www.chameleonforums.com/blogs/intro-to-bio-activity.2429/
Here are some additional thoughts I have about the different layers:
- Drainage layer: height can vary but I find somewhere between 1 and 2 inches to be more than sufficient. Many people use hydroton clay balls for media but other, non-toxic materials work just as well e.g. small rocks, lava rocks, filter sponge mat, egg crate, etc. You don't want anything too fine (like sand) which will reduce the water capacity.
- Separation layer: Keeps substrate from falling into the drainage layer. Anything non-toxic which allows water to pass through easily and blocks substrate will work fine. Most people use fine mesh. I use thin filter mat because it is more effective at containing the substrate.
- Filtration layer: not necessary but useful because active charcoal acts as a magnet for waste compounds and other things that could foul the water in your drainage layer. These waste compounds (like nitrates, nitrites, ammonia) are good for plants so it can be helpful to keep them in the substrate. In addition to putting down a thin layer of active charcoal on top of my separate layer, I also mix a good amount into my substrate for the reasons stated earlier and because springtails love it.
- Substrate layer: you can refer to @cyberlocc 's post for details on the substrate composition. As stated above, I also recommend mixing in a good amount of active charcoal.
- Leaf litter: many people leave this out in their bio-active setups but it is of vital importance as it serves as a primary shelter and food source for your cleanup crew.
- Cleanup crew: Cleanup crew consists of springtails and isopods. These are, by definition, what make bio-active, bio-active. Without a cleanup crew, you just have a planted enclosure, not a bio-active one. If you live in the states, congratulations. There are many places from which you can order springtails and isopods - Josh's Frogs is one of the more popular and reliable sources: https://www.joshsfrogs.com/bioactive.html
I personally recommend the dwarf white isopods as they reproduce quickly, are inexpensive and are ideally suited for the warm, humid conditions of a chameleon enclosure. If you are partial to another species, they should work just fine also (with exception to some species that prefer dryer conditions). Though they are not frequently mentioned in bio-active discussions, I also strongly recommend adding red wriggler earthworms. Their function is similar to isopods though they provide additional benefits to your substrate (cleaning, aeration, fertilization through worm castings, etc.).
Phew!
