When using the getTanks method of the Buildcraft tanks, it considers the entire stack of tanks as one, meaning you get a total of the contents of the entire stack of tanks.
It does not do this for the OpenBlocks tank, which means you cannot (reliably) determine the contents for a OpenBlocks tank (especially if it's odd-shaped).
When using the getTanks method of the Buildcraft tanks, it considers the entire stack of tanks as one, meaning you get a total of the contents of the entire stack of tanks. It does not do this for the OpenBlocks tank, which means you cannot (reliably) determine the contents for a OpenBlocks tank (especially if it's odd-shaped).