The last pic is a storage tank I'm using as a mixing tank - it's a 250 gallon water storage tank where I can mix salt, and keep some on hand in the event of a leak/accident. Easily moved with a pallet jack, and has nice intakes/outlets. Very handy.
Tank is 144"x72"x42" - it looks rather small in the pics, but when you have to lift it, I assure you, it isn't.