The picture is not that clear, but it looks like shedding that still stuck to the skin. I would up and prolong his watering times and see if that works.
One batch are Falys and the other are a cross Ambilobe x Faly. The ones in the picture are Falys. I am rushing to the kitchen to make more ff medium...i am going to need them!
A bigger pump will let you use more nozzles if you plan to expand your collection and you can cover the sides of your cage with a plastic, like a shower curtain.