I've done it a couple times now with this tank. Everytime it acts the same. I would have to believe you in saying that it's the tanks way of showing you it's ticked off.Its crazy you wouldn't think messing with the tank does that, but I recently did that to 2 different systems one to get out peppermint shrimp, and one to get out hitchhiking crabs but disturbed all the rock the same(no sand in either) and put it back. All kinds of algaes and cyano for a couple weeks then just went away. I guess its the systems way of saying its ticked off at you, but then it gets over it.