Yes, nitrates are the end result of the cycling process before it is turned into nitrogen that release at the water surface. Having algae growth is actual a good thing, it consumes nitrates and phosphates adds oxygen to the water and provides a natural food source for fish and pods. The only bad thing is it’s unsightly for use the fish keeper, this why people grow macro algae in there sumps, it does all the good things and grows where we want it to.