FYI you can get RO
water at most Wal-mart stores (culligan puts these in most stores nationwide) for 37 cents/gallon. I bought a bunch of 5 gallon Home Depot buckets & lids for $3-$4 each for transport, they're exactly the same material as camping jugs or the $12 jugs you get at Home Depot (HDPE - high density polyethylene). Also I would get a Rubbermaid BRUTE trash can for mixing and heating the water. Depending on your tank size, they have 20, 32, and 44 gallon sizes. Buy one big enough to do at least 30% of your tank water, if you're using a 55, I'd go with the 32 because then you have enough to do a 50% PWC
in case of emergency. RO
water, whether is comes from Wal-mart or you make it yourself, will be very cold - 55 degrees here in Iowa - so you will need quite some time to heat it, but it's a good idea to mix the salt in for 24 hours if you can anyways.
I bought 4 300W heaters on eBay (some china brand) for $40, and they work great. I figured out a formula for heating, take the # of watts and divide by 3 times the amount of water you're heating in gallons, and that will tell you how many degrees per hour the water will heat up by. So 1200W will heat 40 gallons of water 10 degrees per hour.
I also bought a 150 GPD RO
system from eBay for $114 shipped. Easy to install and use. I just went to Menards/Home Depot/Lowes and bought some extra tubing and a couple of shutoff valves to make it easier and set it up in the basement. Here's the one I got, and I suggest to anyone setting up SW
150GPD 0ppm Reverse Osmosis+(2)DI Aquarium Water Filter - eBay (item 110401195611 end time Mar-07-10 21:34:11 PST)
Best bang for the buck IMO