Mosses also did fine for me too.
Moss have stomata, Riccia does not nor do other liverworts, Vals do, but Hydrilla and Egeria also lack stomata.

Excel may block the CA enzyme of these plants that have to take the CO2 through their outer epidemal layers.

Hydrilla does not take uop Bicarb directly, rather, it produces lots of H+'s and acidifies the water and then reduces the HCO3 to CO2 and takes that up.

Regards,
Tom Barr