I am planning a tank build with approximate measurements of 100"x45"x40", I have decided to use Ames Blue max as my sealant. My question is how much am I going to need to buy? Its $150.00 for 5 gallons.Will 5 gallons be enough or am i way off? This is my first build and im clueless as to how much area this stuff will cover, im sure I will need at least 3 coats right?