AgreeBioballs are not as effective when completely submerged. They work much better in a wet-dry environment.
Ceramic rings are better for a submerged media application (like most canister filters).
why are ceramic rings better in canisters than plastic-bio balls?
8) Bioballs are most effective in an open-air environment (wet/dry - trickle filter) as opposed to a closed system (canisters) because of the oxygen exposure. Trickle filters provide increased oxygenation (as the water is given a larger surface area for oxygen to dissolve in). The increased surface area of well designed bio balls presumably maximises the amount of oxygen dissolving into the water. Oxygen is essential for the conversion of ammonia into nitrities and then to nitrates by aerobic bacteria. Bio balls also work to degas ammonia before bacteria break it down, lessening the load on the filter system. Another advantage of bio balls over other biological media is that the surfaces are impossible to clog up (when used with a prefilter) compared to the micropores of porus ceremic material. The reason is simple: the space within a bioball is large and anything that can clog it up would already have been filtered by the prefilter (such as filter wool, sponge etc). The down side is size & space needed for them to work efficiently. That's why ceramics are better suited in canister setups: minimum space / maximum surface for bacterial growth. "T"can ceramic rings be used as a WetDry filter media?
Would they be better than bioballs due to their higher surface area?