Well, then the question is, what do you have in between the tanks? Is it red hot too or not? If it's not red hot, you're losing a bunch of heat through the extra surface area. But if it is, now you have a bunch more material that's annoyingly reactive (because it's red hot) and may decide to melt down into a pool of red-hot material on the ground, letting the lye tanks cool down and possibly spill.
