Join Date: Jul 2010
Location: Outside Philadelphia, PA
If you have one of the larger Eheims, you might be able to use regular plumbing parts. For each double tap you'd need two hose barbs, two threaded valves, two threaded couplings, and a threaded union. There are other ways you can do the same thing with slightly different parts, but because hose barbs are usually threaded, it makes sense to use threaded parts for everything.
Use teflon tape on the male threads of each connection and assemble in this order hose barb, valve, threaded coupling, union, threaded coupling, valve, hose barb.