I second, and third, what 54seaweed stated. The state of filtration in aquaria now has moved past the undergravel stage. See Filter (aquarium) - Wikipedia, the free encyclopedia
.. If they clog, they can be very difficult to clear out, depending on where the clog is located.
HOBs are fine...and you don't really need to keep buying cartridges for them. I keep SeaChem Matrix (for biofiltration) in both of mine along with some polyfill, to get the big stuff out. Super simple, and near zero maintenance, except when rinsing the polyfill in some tank water to clean it out. Other than that, every month or two I clean the impeller and wipe out the inside of the box during a water change, and every 6 months I regenerate my Purigen.