would appreciate some help? i have on 1 of my rocks some type of algea looks like grass is this bad and if so what would be the best way to get rid of it? my lighting is 3 40w sylvania f40/865D 6500k's 1 actinic 40w 1 coralife 50/50 could it be lighting? its a 55 gal, i have 60lbs encrusted...