The watertanks spawning in a village are not multiblock and I have to replace one of them to make them multiblock. http://b.1339.cf/cfnzqyo.png

When breaking a colum of a multiblock watertank it does not re-form unless I replace one of the blocks. http://b.1339.cf/cubevyc.png

The first one I can fix, the second one I could fix, but I will not, because else the number of operations needed to perform checks and form sub multiblocks would be to large.

Have you considered checking the code forestry uses for its multiblocks?

No, but Forestry has limited sizes, and if you break a column it wont reform either.