Macroalgae has many benefits to its use within a refugium or even a planted marine aquarium, but there are also several drawbacks that can turn your beautiful tank into a nightmare. For starters, this stuff grows really fast. While this is great for a refugium, it’s not so great for the display. If a piece of the algae breaks looks and gets into the display portion of your system, it can quickly take hold and become quite the nuisance. In addition to the fast growth, some macroalgae species have been known to sexually reproduce in captivity, which is just as bad as it sounds. Portions of the algae turn white and release clouds of spores and other reproductive materials in the water, which can quickly lead to a full tank crash. If you do decide to use macroalgae, just keep these risks in mind and take whatever precautions necessary to mitigate these issues.