Your redfoot probably had a protist inbalance in the intestines. If the stool appears gooey and greeninsh-brown I have always used flagyl (metronidizole) and it has always been successful. I usually give it to them 3 times with 10 days in between.

Most wild caught or ones kept outdoors have an intestinal outbreak when brought into captivity or transferred to someone. Stress seems to play a role. 15-20 years ago most people without access to a good vet lost a lot of wild caught tortoises to intestinal parasites. I usually use Panacur and Flagyl in combination when I get a tortoise with loose stool. I can usually see the protists under my microscope. If it does not clear up in about 10-20 days with treatment than it is probably something bacterial and you would need a vet to run a culture.