Thanks to a steady trickle of donations plus a bit of my own money I was finally able to get these extra enclosures and the dremel necessary for expanding Hampture. You can see the Mk. II habitat in the back for a size comparison, and inspirational reading material in the lower right. :3Next I'll need a sealed wood panel to bolt them to. I'll want them very secure before I glue/seal the tubes in place as trying to bolt them down after the fact might cause cracks.
Air will flow in to either of the two side enclosures, through the main exercise room, then into the bottom enclosure and out a one-way air release valve. This model will release air directly into the water as the Mk. II taught me that maintaining a 1 atmosphere habitat via air return tube requires precisely measured pump strength or you wind up with a slight overpressure that forces bubbles through the seal (as seen in the video). That's not a big deal for a few hours here and there but I'd rather the seals not somehow weaken over time as a result, so the Mk. III habitat will be ambient pressure. At 8 feet deep, the increase in pressure won't be significant enough for the hamster to so much as feel it, although I may want to raise/lower it at a leisurely pace to be on the safe side.
Side note; The Mk.III will have a power cable instead of an air return tube, this time for powering the heating pads, one for each room. I can't really rely on battery power for that many heaters and the clover aquaculture room will require grow lights. Still shopping around for compact grow LED arrays.
We're close, guys. This is really gonna happen.