I have been running a plenum system on my tank for a few years now. I also have a sump with some rock and macro algea in it. I have a skimmer but rarely ever run it.
The tank is 90 gallons, 60 plus pounds of live rock, probably 3" of sand over the plenum. I used to struggle with hair algea and occasionally cyano, but since I have been more consistent with water changes (5 gallons every week), and cut back my feedings (daily but half as much), I have seen the hair algea start to slip away. And I believe i have restored balance to the force.
I was thinking, with the plenum, maybe I don’t need the sump, and I’m not even using the skimmer.
Any thoughts on if it would be a bad idea to disassemble the sump and just keep it simple?
That said, I’m in the “if it isn’t broken…” camp. If your system is stable with what you have I tend to say leave it be. If you aren’t using the sump at all and it is just taking space you could take it off. You may want that space back later though.