Yep, thats part of the plan. I will keep an eye on them. On a different note...Just keep an eye for any fighting, because it is common amongst tangs, especially in smaller tanks. If you notice a lot of "pacing" in a sense, it is time for an upgrade. When we had the yellow tang in the 56 gallon he started pacing towards the end. He'd swim back and forth fast, and up and down. I knew he wasn't happy, so to a new home he went, and later died. If you upgrade in the future make sure it is a 6foot+ tank, as that is what they truly need. The reason I went with a tomini (besides being not as often seen in the trade), was its small size.
I picked up a 20L today, perfect fit underneath my stand and most of the acrlyic pieces should be able to be cut down another inch and fit perfectly in there. My biggest question at this point is, is a bubble trap really needed? It seems to add alot of complexity to the setup as far as sealing it properly. Can I use something like a sock filter/piece of rock in the drain area?