The temperature effect I'm expecting is because of differential heating with subsequent pressure changes across the manifold and therefore gas movement back and forth between tanks. As the sun moves across the sky it hits one tank before the other, and likewise leaves one before the other, so I'm expecting a little movement of gas from one tank to the other and back. But I'll find out in a few hours here when I do the "final analysis."Tassie Diver:For the record - my money is on the bouncing round in the back of the truck and exposure to temperature fluctations making bugger all difference!
Rick