I have hauled 4-6 pd Bass in hot weather and I use a oxygen tank just like the one used for a cutting torch. I has a small airstone attached to the end of my tubing with a weight to hold it at the bottom. I also have a circulator that runs off of a car battery to constantly turn the water. I have a 340 gallon fish hauler that I have finally figured out. It sloshes a lot less when you have it virtually full verses having it halfway full. Just my observations.