I though it might do better in more water, every inch its outta water is that much harder the pump as to work.
The bulkhead are just a 1/2" coupler sawed in half so the pipe can slide all the way through. Glue the ring on, slide on the oring, put that through the hole in the acrylic, install the other oring, apply a little glue and slide the other ring on, pressing them together to form the seal. It is permanent, but it seals well and still lets me rotate the pipes. Uniseals may work, but I think they require a larger hole.