If noise a concern, think about drilling for 2 bulkheads for your drain then you can set up a Herbie. Might also want to drill your display for a return line, little cleaner and easier for a hood/canopy rather than going over the top.
Surprised $300 for a sump, should be able to get a used aquarium cheap (
20g here or
30g here) a few few pieces of glass cut for baffles (~$20) and a bit a silicone and you're done.