Sometimes people get a bright orange growth, especially on tanks with lower nutrients, or after the scrubber lowered the nutrients that used to be higher. This type of growth fills in all the holes in a screen, and/or coats the rocky surfaces solidly. This growth is simply the type that is best suited for high-illumination and low nutrients. It's just harder to clean because it's thicker. If a screen, try to get all the growth out of all the holes with a brush

If you don't like the orange and want to try something different, first (for a waterfall) always make sure you have enough flow; here is very high flow example: ). Water should always be flowing across the bottom of the screen all the way across. Bubble upflows don't have this concern.

Try reducing the illumination amount, but keep the same hours. If you can't reduce the amount, then reduce hours by 2 per day. Or, turn off the lights on one side so that there is only light on the other side.

Try feeding more nori. It has lots of iron, which really helps yellow growth, and might help orange growth too.

Try dosing iron, and maybe iodine. If you feed enough nori, however, you should not need to dose.