WARNING: putting multiple tanks on the same system can crash the game. This is a very expensive 1x1 fluid storage tank that holds up to 183 billion fluid. It used to be infinite, but this is the game limitation in Factorio 2.0.6. It is necessary to put a pump at the output, otherwise only part of the fluids inside the tank will drain out. The tank costs as much as 100 regular fluid storage tanks (2000 iron plates and 500 steel plates) OR you can make it directly using 100 fluid tanks. Either way, it takes a LONG time to craft.