That's alotta pump....
Their video says "supports up to 4 sprayers..."
Remember that as your battery discharges during use, the amp draw goes up.
So, say the pump is 200 watts and your new battery is resting at 13.1 volts. That's ~15.26 amps when you throw the switch.
Take your shower, the battery drops to 12.5 volts. Now you're at 16 amps.
And it keeps going like that until your battery doesn't have enough voltage to power your fridge or pump.
I'd get solar or run the truck while you use this thing. Or get a smaller pump.