300 gallon metal tanks with sweep agitation blades mostly move the product contents near the outside walls of the storage tank. The heavy paddles usually rotate very slowly and are driven by cumbersome gears, chains, and pulleys. The product near the center of the tank may never even get mixed at all!
To observe this, try this revealing experiment:
First take a can of paint, secondly take a paint stir stick. Now stir the contents using the stir stick only along the inside edge of the paint can slowly. Try to emulate the speed of a paddle moving around the inside of a storage tank. What happens to the contents in the center of the paint can? Hardly moves or mixes at all doesn't it?
The re-circulation system that comes with the AK Tote, Drum, Portable, 130 and 230 Sprayers is absolutely amazing. Your sealer mixes up in 3 to 4 minutes and ready to apply.