You must be DISMOUNTED when trying to initially get the microbe swarm to aggro the turtle. After that, you may re-mount. As long as a player (any tribe, possibly unintended) is in very close proximity to the turtle, it will tame at a static rate regardless of level. It takes ~30-45 mins to tame without reset.
They have patched the render range range so ignore any tips that say to leave render as it will no longer. Guess I’m stuck with the turtles I have, I’ve spent three hours trying to take one of these things and had it walk out of the water which reset it taming! It was at 80% that time. Never got it above 20 after that. What he for the saber tooth salmon that spawn to kill the swarm if they bite the turtle it resets to zero and you start over. Extremely frustrating way to tame a creature. I would like to beat whoever came up with this idea.