Ice man its a little cyano, pretty typical for newly setup tanks with sandbeds. Probibly the result of some bacterial build up that died off after the initail cycle. you will probibly see it come and go for a little while
The first year of a tanks life you will experiance periodic algae blooms. This is normal and nothing to be alramed about. You can either remove it or leave it. It will not harm the livestock at all; it just looks kinda bad.