There are so many factors that contribute to algae issues, but is there one that stands out above the rest as the most significant?  Is it even possible to generalize all the types of algae and identify a single cause for brown algae, green algae, blue green algae (which is actually bacteria), etc?

In my opinion there is one characteristic common to all aquatic settings that have been overrun by algae, and it is something that boils down to the essence of life.  Luckily for us, this one characteristic is also one that we potentially have the most control over in our aquariums, ponds, and even pools.

I asked a friend of mine if he knew what the primary cause of algae problems is, and he said, “It’s gotta be light. Almost everyone who has algae in their [fish] tank has too much light.”  I can agree that lighting is definitely a major factor in algae control and in the environments that we care about, is easily a contender for the top cause.  But just as food for thought and for the sake of argument, consider that scientists have been able to create a form of algae that grows without light.  Pretty crazy, right?  So is there some other algae growth requirement that modern science can’t alter or remove?

When it comes down to it, the single most significant cause of algae problems is the availability of nutrients.  We now know that it is possible to create algae that grows without light, but nutrients provide the bare building blocks of life that algae and all other organisms need to live.  This concept may seem obvious to some but if you sit and really think about it, you can begin to theorize why there might be excess algae in your pond or aquarium.

Where might the nutrients that support this algae growth be coming from?  Could it be the fish?  Perhaps the fish food?  If you keep live plants and fertilize, could it come from the ferts?

How about all of the above?