It’s inevitable that some form of algae outbreak will form within your hydroponic system. It’s a problem if it starts to take over everything because you’ll pretty much have to reboot your system. (Clean out and sanitize) This isn’t a huge deal but more of a setback in other words. The biggest problem is when it starts to grow wild during a plant growth cycle and you possibly lose all of your hard work and effort. The best chance at avoiding bigger issues is to plan and prepare. A little bit of algae however isn’t the end of the world as long as it is controlled.