What makes yumas lose color? I have a few that had more contrast when I bought them...one was greenish with pink outer skirt, and the others were purple with orange tips. now they are pretty much orange/brown, but they are large. Sometimes when they are moderately deflated, the color kinda comes back (especially when it's just actinics.) but still not like when I bought them. Is it just the nutrient load? Iodine?