On Saturday, November 29, 2014 2:33:08 AM UTC-5, Harry K wrote:
On Friday, November 28, 2014 10:35:59 AM UTC-8, trader_4 wrote:
On Friday, November 28, 2014 1:00:58 PM UTC-5, HerHusband wrote:

My first thought is if it's just for a day, whatever min is in
that 80 gallon tank, ie assuming it's almost about to kick the
pump on when power goes out, would be enough for me. Or that
plus a couple of 5 gallon jugs.

One easy option would be to adjust the kick in pressure on your 80
tank so that it doesn't get as low before it kicks on. That should
give you a min of 20 gallons to work with. Or add
that second tank in series, so that it's always full of water, no
air. If power goes out, you'd only have pressurized water for
about as long as you do now. But you could still draw X gallons,
X being the size of the additional tank into buckets.

Wrong. Both tanks will fill and empty simultaneously. Basically you would be simulating one double size tank as far as system operation goes.

snip

Harry K

Not wrong. You don't have air or an air bladder in the second tank.
The second tank is 100% water. Water from the existing tank comes into
the bottom. Water supply to the house comes out the top. The only air
is in the bladder in his existing tank.