What kind of pumps did you use in your system? Do they "chatter" when backloaded?
I used submersible commercial pumps ranging from 25W to 100W depending on the size of my aquarium (20G -220G). A single 25W for the smaller aquariums.
Yes, the pumps do chatter when the UG gets clogged but hovering the UG solves the problem. The UG takes about a 100 days to get clogged enough to make the pumps chatter.
If you have a choice, you have a problem, till you elect your choice. No choice, no problem, only consequences, learn to live with them.