When she poured water into the gallon for 6 minutes, the total time in seconds she took is 6 minutes * 60 seconds/minute = <<6*60=360>>360 seconds.
If in 20 seconds she poured 1 gallon of water into the tank, in 360 seconds, she poured 360 seconds / 20 seconds/gallon = <<360/20/1=18>>18 gallons of water into the tank.
Aubriella will have to pour 50 gallons - 18 gallons = <<50-18=32>>32 more gallons into the tank to fill the tank.
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