Oh, in regards to the 1000 gal (or more) tank in the basement, I have thought of keeping a tank like that outside one day when we own a joint rather than rent. That would solve the problems of water damage to the house due to evaporation. You could also set it up so there was a roof over it and a rainwater tank nearby which directly topped up water lost due to evaporation also, ideally have two so you can premix saltwater for water changes (depending on the tanksize of course, really big and you'd only need to do top-ups) in one and freshwater in the other. Place it in the yard right next to the loungeroom and knock out part of the outside wall and make that side of the tank glass which will replace the part of the wall that was knocked out and bang! Instant giant fishtank which can be enjoyed inside while escaping the issues which would be created by having the whole tank in the house.
If you were to go one better and build a shed around the tank rather than just a roof over it then you could even have it as a tropical tank rather than a coldwater tank because heating would be alot easier. There is also ways to make heating easier as well if you do it this way because only one wall would have to be glass (the one replacing the house wall), the rest could be made of concrete, etc and you could implant them heating rods that they use in houses into the walls and floor. I don't know if you could use these as the primary heating source, but it could be used in tandem with other methods as well such as heating the shed, etc. Line the walls and roof of the shed with insulation batts to minimise heat loss and install a dehumidifier system which many people use in their fish rooms anyhow. Lighting could be suplemented (not replaced, but suplemented, thus cutting down a little on a big problem, of course you would need to place the tank in a good position to gain the most from this) by a skylight built into the shed roof which could have a piece of roofing to slide across it during the night or on cold days to stop heat leaving.
I think by setting up a system in this way would make a tank like this alot more feasable, especially costs-wise considering that a mostly concrete tank would be alot more cheaper than an all glass one. You could also cut back alot of cost by making your own base rock and curing it in the tank itself before seeding and eventually stocking, of course you'd have to do this before making the shed and would need ample space to create a mold large enough as well as hire a crane to shift it into place. Creating your own rock would cut back a ton of costs and, even though it sounds daunting, could be achived by knocking up a large frame similar to the ones used by concreters to build walls, etc, and fill it with sand. Then just dig out random shapes and pour in the rock mix which you'd make with a common cement mixer, let it dry over a few days and open the mold, scrape off the sand then lift it into the tank with a crane to cure. If you put a little thought into it you could re-use the mold over and over again until you have enough rock. I would make the mold easy to assemble and disassemble while the rock is in it so I would just have to move in over a few meters, set it up again and re-pour, recast then move it again until I had enough then hire the crane for one day rather than over and over again each time I finished a piece, thus saving on costs again).
In all honesty, in an enviroment this big I don't think it would take too long for life to propogate and spread if you were to seed with a fair amount of live sand and live rock (which can in turn be created to some degree in an already existing, mature system - preferably a few each with their own sourced rock and sand to get as much diversity as possible - with a little patience) buy some pods in bulk (or breed them yourself), put in some corals which spread fast (which can also be propogated in an existing tank to at least a small degree, depending on patience) and sit back and wait for around 12 months or so before adding any fish to enable plenty of time for everything to build up in numbers. You could go even further to reduce running costs by hooking some stuff up to solar panels run from the roof of the house too, they wouldn't create enough juice to power everything most likely, but they would run perhaps the heating for instance, that in itself would be a plus.
Anyhow, they are just a couple of things I have put thought into. I'm sure there are plenty of other things you could come up with but there are a couple of main ones I have thought of to make a tank like that more attainable. It would be a daunting task and would still cost a bit, but I think there are ways to make it something the average joe could do with alot of DIY rather than being restricted to a millionaire's budget. It would take time too, I would set aside at least 2 years after the tank is set up and curing before adding any fish just to promote the spreading of coraline algae, microlife and such alone (I am probably a little over cautious, but I'd prefer to wait longer and be certain than rush and bugger things up at so fundamental a level - the small fellas really are the lifeblood of a successful reef). That aside I am guessing at least 18 months to do the actual building, depending on how much free time you have as well as how much you want to do yourself and money restrictions. Factor into that exactly how DIY you want to be when it comes to getting enough pods and live sand and live rock to seed the tank and you could be looking at at least five years or so on top of that, depending on the tanks you already own. In all honesty though, that is probably more patience than most people have and shelling out a bare minimum of a thousand bucks extra, and in all likelihood alot more (depending on local prices and how much you want to suplement as well as tank size), on live sand and live rock to supplement your own propogation of microlife, corals, etc is the more feasable choice.
To anybody reading this post who is even thinking of taking on such a monumental task one day (of which I must admit I am 100% guilty of, the mere thought of getting stuck into such a project makes me giddy

) then all I can say is make sure you have mountains of patience, do tons of research, walk into it with more ideas than the handful I have listed here (you will need them because in all honesty, mine could probably be vasty improved, may be impractical in practice and utterly expanded upon), plan full on for at least a year before even buying a single thing, good luck and by God, you'd better make a photo diary of the job so we can all see it
