I'm trying to make a xycraft tank out of smooth stone by digging it straight out of a wall. The interior volume is 10x9x7, no items inside and all blocks being mostly naturally formed smooth stone and some that I placed to replace removed dirt, gravel and ores. On the 'front' in the cave that I'm carving this tank out of is 3 rows of glass viewer in the middle three rows of the 9 wide wall and a single valve. When I right click the valve the tank won't form. Double checked all blocks are smooth stone (except valve and glass viewers). Any ideas?