I recently purchased this Royal Exclusiv 25w pump and had to acquire some metric unions for it. Their website states that the inlet and outlet are 32mm and 25mm so I ordered those unions. The 25mm fits perfectly but the 32mm does not screw on and is a little big. It’s not overly big, but just big enough that it won’t tighten. Any ideas? The metric unions I ordered are from Coral Vue (who failed to ship part of my order).