Do not forget to add a dechlorinator to your water change regimen for the big tank, like Amquel+. While free chlorine will dissipate out of water, chloramines will not. Ageing the water is great for stabilizing supersaturated oxygen, but given the level of water treatment chemicals in the US Municipal systems, a few drops of a dechlorinator goes a long way to preventing headaches. An all in one product like the Amquel or Prime will also remove traces of copper and lead left over from the plumbing and water treatment plant.
On a final note, do a water chemistry test on a sample of the bottled water you plan to use. You may be surprised what you find!
When I was forced to use bottled water (for the last two years) I found CostCo's Kirkland Signature Spring Water to be very cost effective and safe.