I've been working on a prototype of a betta barracks that I'll be building out. I just want to make sure I'm using the right fittings, that I can trust the thing to work when I'm not home and have it not flood the house. These will be tied together on a centralized recirculating system. There will be 24 of them together on the first phase of the buildout, but I'm designing this system to be able to expand.

The return bulkhead is some cheap reverse osmosis (RO) 1/4" push-to-connect bulkhead that I picked up on Amazon. They don't come with any gaskets so I'll have to apply liberal doses of silicone. The overflow is a Lifegard Aquatics brand 1/2" slip x threaded unit. I've also added a 1/2" low profile surface skimmer with a slip fitting. I couldn't be happier with that part of it. When these are up and running, the water flow will barely be a trickle, so this will keep up quite easily.