My mississippi map had some alage on his back and i read that if you take a new toothbrush and scrub their back and it worked for a little bit but then i went on a 4 1/2 week trip and gave my turtles to my uncle to take care of my turtles and after i got them back squirt had his alage was gone, but they left colorless blotches on his shell! Is this even normal?? Thanks!