opinions/advice wanted on waterchange idea

[khaosinc]

So, I'm rapidly gearing up for building a tank way beyond my skill level, and am hoping to make many of the chores as painless as possible.

My idea is to have 2 tanks in the fish room, of about 200 gallons and have them plumbed in to the sump with a smaller return pump. Lots of plumbing and valves to make them easy to isolate from each other, and easy to drain.

Basically my idea is to have one tank be part of the system at any given time, and the other to mix my next water change. When the time comes for a water change, kill the pump, turn off or on a couple of valves, and poof... water change is done... drain other tank, dump in a bucket of salt, spend 2 days filling with RODI water, and with aid of an easily swappable mixing pump next water change is ready to go.

Empty these tanks are pretty easy to move to get washed out. Any reasons this might be a bad idea that outweighs having a couple hundred extra gallons in the system? Rough guess puts this at about a 15% water change for reference.

[khaosinc]

My assumption is that assuming I stick with one brand of salt, that 1 bucket should be pretty close to a consistant mix of NSW and I could mark on the tank and include an auto shut off (testing before using of course) to give me pretty close to the same water each time I do a water change.

[heap]

i do something sort of similar with a 55 gallon barrel - it was cheaper than another glass or acrylic tank, and being more vertical, it saved some floorspace.

i ended up pulling it from normal circulation after awhile, however...i just use it to mix new SW prior to a water change. the fish room for my main tank is the garage, and it just added to the volume of water sitting in rather chilly air during winter months.

generally speaking, tho...it worked out well, and even tho i don't keep it plumbed into the system constantly anymore, it's still useful.

[khaosinc]

I've been talking to one of the guys that brings us presents (read that parts) at work... and he's found me a pretty good deal on 250 gallon vertical/cylendrical (however you spell it) tanks with a threaded bottom outlet. My Tape measure claims I can hide 3 of these (one for a rodi top off) pretty easily in the room where the 'other' magic happens. I figure once I mark where I need the water level... everything becomes a no brainer.. and I have one less thing to worry about.