nullpointer exception in alloy tank

I have a smeltery with a drain attatched to an ie fluid pump to extract molten ardite and cobalt into a ie fluid router which then sorts the fluid to two fluid tanks on opposite sides of an alloy tank. When I melt some ardite ore, as soon as it finishes melting the server crashes.

crash reports:
https://pastebin.com/qFU3zAnH
https://pastebin.com/1QSmgKNu

Duplicate of #43, update Tinkers Construct.