It wasn't the threaded pipes that were leaking, sorry for the confusion. These are the pipes that I needed to stick teflon around until it created a seal.
My powerhead pushes from the back left corner and is pointed towards the front right corner. That picture must have been taken when it was pushing 4,000 GPH towards that corner.
This is how I understand this.. You dont have a match between those pipes and your bulkhead. To use teflon is attempting to fix a problem that thould not exist. Basically those tubes or your bulkheards are mismatched. one or the other is likely metric and the other is standard fittings. IF the tubes you show are metric, you need metric bulkheads. Its common when buying overseas parts and getting fittings locally. Not sure if that is your situation but I have run into it a couple times before I realized with the problem was.