Busdriver, luckily, here in earthquake country, we don't do raised foundations. I'm sure she's on a slab, but good thinking!
The biggest issue we have here, Pitmam, is we pay more for electricity than anyone else in the nation. Obviously, I don't know where your power bill comes in each month, but consider that more wattage used will be pushing you into higher tier billing from PG&E. While we pay about 11 cents per kilowatt hour as a base, it jumps up to over 22 cents and even over 35 cents per KwH as you use more power than your baseline numbers.
A 180 or 220 puts you into a 6 foot tank, which means 3 MH bulbs. That's presumably 250w times 8-10 hrs per day, for that extra bulb alone. That equates to 2-3 KwH per day, which at top tier is $1/day, for that single bulb alone. Now add in the silent killers, all the items that run 24/7 (all those darned pumps!). Those Koralias aren't going to cut it on a large tank any more, unless you have a whole army of them. I wouldn't put any less than 6 of the K4's on a 220g. Luckily, they're low power. 6 of them makes only about 50w usage, but it's still non-stop.
A local reefer is considering spending $2K on a Bubble King skimmer just because it uses 300w less power than his current one. For him, that represents $100/month in savings, so it would pay for itself in 2 years.
Not to totally discourage you, because large tanks are AMAZING. I just wanted to make sure you hadn't overlooked the biggest hobby killer in our area. (plus, you still need to hop into the local forums, and meet up with locals, you know....)
