Yes I prep my water in storage containers in our laundry room. And my two tanks are 150L (40 US Gallon) so its manageable - not so easy with a 700 liter tank. I do not consider the aging or degassing of the water to be super essential. It's just that little bit of extra stability that I can add. With a 700 liter tank I don't think there would be a practical way for me to do this. There are systems that can scrub CO2 (bring the level down to the natural equilibrium), but those are costly.
Cheers,
Michael