Cleaning Skimmer Box

A quick question about my skimmer box. Its been in operation for about a year, and I havent cleaned it because it is sort of acting as a mini fuge with the lights hitting it (I think). It has all sorts of growths inside and its coverd in a red algea and it also has some spots of coraline algea on the outside. Should I leave it alone, or is it doing some harm not being cleaned for a year with all that thick red and brown ?