The volume of water that is in the tank initially is 3/4*8000 = <<3/4*8000=6000>>6000 gallons.
When Daxton empties 40% of the water, he pumps out 40/100*6000 = <<2400=2400>>2400 gallons of water.
The total volume of water remaining in the tank is 6000-2400 = <<6000-2400=3600>>3600 gallons.
Daxton then fills the tank with 30/100*3600 = <<30/100*3600=1080>>1080 gallons of water.
The final volume of water in the tank is 3600+1080 = <<3600+1080=4680>>4680 gallons.
#### 4680