Building the removable second floor

I've cut out the piece of plastic that will serve as the second floor of the new habitat. Also measured and cut the dowels that will support it and found all of the nuts/bolts I'll need for mounting the dowels, the ballast pods and the skylight. 

This thing really is big. I'm not sure how apparent it is from the pic below (I included one of the running saucers for scale) but even one floor of it is about 30% larger than Hambase Alpha. And there'll be two such floors, with enough vertical room that both could have a running wheel if necessary. Or two each?

Tomorrow I'll run out to Home Depot and look for a piece of lexan suitably sized for the 'skylight'. Probably the same precut piece I also used as the front and side windows for my diving helmet as they happen to be exactly the right size for this as well.

Adding in a skylight is only necessary to begin with because the enclosure didn't turn out to have a transparent lid as advertised. It bothers me that I'll have to compromise the integrity of the enclosure so much by cutting out a frame for the lexan window, mounting it with bolts and sealing it with silicone/cyanoacrylate, but as the lid is very rigid and doesn't flex much I expect to be able to make it very watertight. The opaque rim of the lid will also give me someplace discreet to mount down-facing LED light strips later on.

As an aside, I tried to sink this sumbitch in the tub using all six of the 5lb lead block weights I have now but it wouldn't sink. Which means the dual Otterbox 3000 ballast pods I used for Hambase Alpha will not cut it here. Even three of them won't be sufficient. Luckily the same company makes a container with the same footprint, but twice as 'deep', the Otterbox 3500. This means I can fit four block weights (20lbs) into each ballast pod.

This should allow me to mount either two (for a total of 40lbs) or three (for a total of 60lbs) as necessary. At this point I strongly suspect it'll take three of 'em. This will put the ground floor up a little bit higher than Hambase Alpha's, but when I get around to connecting them with the modular gate/tube system, the tubing is flexible so a slight elevation difference shouldn't be a big deal.

Here's the type of weight I need > (Link) There it appears to be sold in lots of 8. There are two such lots remaining. Buying both would give me enough weights for Hambase Delta, plus four extra I could use for the removable food module and the removable waste module. If a wealthy, generous, mentally unbalanced person is reading this and would like to greatly accelerate work on this project for his or her own perverse satisfaction, I'll need about $220 to buy the weights I need plus another $60 for 3x Otterbox 3500.

Very Large Habitat Concept

This one's a bit "outside the box". It's a large ham ham colony based on this kind of inflatable underwater shelter:

As you can see, a few people have done this for their own use, and luckily for me when done the way they did it, it isn't especially expensive. The second one is of particular interest as it needs no weights! It is secured to a crevice in the rocky surface of the bottom. Wherever it's possible to do this, this method is ideal as 99% of the hassle of doing this sort of thing is weighing down all that air. Anyway, on to the main attraction:

This assumes no such crevice will happen to be handy for securing the thing and that weights (many buckets of sand I will fill underwater, then secure the sheet of plastic to, then release air from a scuba tank into it) will be necessary. As you can see, the hambro living space consists of the same type of cage they live in on land, made from stacked, bolted together transparent plastic storage bins with a climbing tube to get between floors.  

These simply float on the "surface" of the water inside the big bubble of trapped air. Holes in the lid allow fresh air to circulate into the cages, as usual, and fresh air is sent down to the inflatable dome shelter using the same oil free electric air compressor I used to supply my diving helmet. This will ensure an ample airflow suitable for more hamsters than I could reasonably fit in the thing.
  

Crucially, this lets me surface inside of it to open the cages, clean out the 'dirty spots', resupply food and water, etc. without bringing any of it up to the surface. And because of the more powerful compressor, this thing can be up to 21 feet deep if I ever want to surface the hams for any reason or with a yet more powerful compressor, up to 50 feet deep (the limit of using normal air before the oxygen content in it becomes toxic) if I was content for them to live down there for their entire lifespan (as I would be unable to safely surface them due to the nitrogen in their tissues).

I think I could fit about four floating cages in there and still have enough room to surface and maintain them. With 3 hams per cage, that's a population of 12. I could go higher but I can usually only find siblings in groups of 3 or less.

This would be very fault tolerant as well. The enclosures themselves don't have to be sealable or remotely watertight around the rims, just able to float stably. Overpressure inflatable shelters are in general pretty foolproof, just not commonly large enough for a person to live in. For hamsters however, it's massive, and if you were going to conduct an experiment to determine what effects living underwater for several generations has on complex mammals, this would be the way to do it.

New enclosure arrives, and it's huge

Moreso than I expected. Easily the same volume as the 2 story cage they live in on land (I set it next to the existing habitat for comparison. That's the heater pad inside it.) Just one problem, the lid is opaque. I can't exchange it because according to the site, the manufacturer no longer makes the fully transparent version and they have none of that model in stock. So, I will at some point be adding a large transparent lexan window into the lid to allow light through. Maybe some LEDs around the interior rim?

New dry case purchased

It'll take quite a while to get here as it's coming from China. Which is also the reason for the insane $71 shipping. But to the best of my knowledge this is the largest transparent dry case available, which means a habitat roughly twice the interior volume of the one I'm using now. And it will become the hub for a system of modular interconnecting habitats to follow. Stay tuned.