I ran my tank with a RFUG, with the inlet water to it coming from my external reactor. My thought was it would introduce CO2 rich water right under all of the plants, thus greatly reducing the problems involved in trying to get CO2 down to all of the plants. I was hoping that my algae problems would drop down considerably as a result.
The RFUG worked great for polishing the water, giving me the clearest, most invisible water I have ever had in an aquarium. And, there was no evidence of any problem getting CO2 into the tank - the drop checker was reliably green day after day, with overgrown or freshly pruned plants. But, my algae problems didn't seem to be improved. Shortly after that I finally gave in and agreed that the secret to avoiding algae was to use lower light intensity.
I now have a RFUG in a 65 gallon riparium, working very well for keeping the water clean, but I no longer use CO2.