I don't know I'm stumped, if your thinking it has something to do with light maybe try a different brand and see what happens. When i was asking about the water i was thinking if you had a water softener that you add salt into and your not bypassing it maybe the high salt content in the water was effecting his skin. But ya from answers to those questions you seem to be doing everything right so I don't know what to think, maybe one of the moderators will come on in the next day or so and may have some suggestions.