The price jumps because the pressure differences in the uses, even though it is only 1/8th inch thicker, the material must be much stronger for higher pressure. I think I'm explaining this poorly, but I hope you understand what I'm trying to say. The point is even at a LFS it may not be much cheaper because they don't actually produce the tubing, but maybe they make different products for different uses so it is not as strong. If you do find thinner (= less expensive) material for aquarium use we don't have the kind of pressure to make a difference so it will not be a problem.