cooling system questions

[Jeremy_5]

I have a couple questions concering the cooling system. I just flushed my engine and radiator, but when I re-filled it up the manual said it should take 21 quarts so just a little over 5 gallons, but I only put about 3 and half gallons of the pre-mixed antifreeze and water. Did I have that much water left in the system from flushing it? Isn't that going to throw my coolant to water ratio way off?

Also to clean the recovery tank do I just take it off dump it out and then refill it with some coolant? The level never seems to rise or fall in the recovery tank is that normal. And last question where does the hose go that comes out of the recovery tank, it looks like it goes into the firewall, but why, shouldn't it go to the radiator so it can recover excess coolant when the radiator pressure drops?