i have this on my rays as well, in symmetrical areas around the disc like patterning, each set at equal distances. around the eyes as well. i'm curious as to if it is due to the effects of keeping in hard water? my city water is complete crap. 20-24 grains per gallon of water hardness, with a local tds reading of 320+ depending on the given day. it is DISGUSTING!
are your rays in hard water as well?