Feed C02 into RUGF intake?

[Bill Stock]

Has anyone does this? Seems like a natural?

[Dances With Ferrets]

I've done the same thing in a less direct sort of way.... I have it
running into a fluval canister filter, then straight down the UGF tube
in a modified reverse-flow type of setup. Works very well at both
completely dissolving the CO2 and at providing a well-oxygenated
gravel bed.