Don’t Leave Your Aquarium Light on Too Much!
THE PROBLEM: In my last Aquarium Blog, I covered the issue of over-feeding your fish and the effects it has on your aquarium. Today, I want to discuss another very common cause for dirty fish tanks, especially green water and algae growth: leaving the aquarium lights on for more than 8 hours a day, and sometimes indefinitely. Whenever someone has approached me complaining that they have always have algae growing all over their aquarium, and it’s a constant battle cleaning it, my first question is “How often is your light on?” On many occasions, the answer is something to the effect of “Oh, we never turn it off!” Also, positioning the aquarium near a window can result in over-exposure to sunlight (even indirect sunlight); this also is a frequent culprit of excess algae growth.
THE ISSUES: Like all other animals, fish do require a balanced day and night cycle. While they lack eyelids and do not actually “sleep” we do, they do have periods of inactivity where they rest. Imagine living in a bright room all day and all night, and the lights are never turned off. Then, try to imagine falling asleep in that environment! If that weren’t difficult enough, try doing it without closing your eyes. Fun Fact: Fish do not have eyelids, so you can see that they certainly appreciate having that aquarium light going off at night so they can rest, too. And like I mentioned before, too much light can cause unwanted algae to proliferate, which can become an uphill battle to control if allowed to do so.
THE SOLUTION: Fish can typically see just fine using only the ambient light in the room, so try to restrict the time the aquarium light is on to the times you are actually around to enjoy it (6-8 hours is plenty!). Putting the lights on an automatic timer can help ensure they do not stay any longer than necessary, and you will not have to worry about remembering to turn them on or off every day! This can save wear-and-tear on the on/off switches of the light fixture, and it makes for one less thing to be concerned about should you be out of the house late or out of town.
When I had my last aquarium set-up, I had the lights set to turn on from 4:30pm to about 9:30pm. That gave the fish plenty of time to “wake up” before my wife and I got home from work at 5pm, and we both could enjoy the aquarium all evening right up until bedtime. I even had live plants growing in the tank, and the 5-hour photoperiod was plenty for keeping them robust and healthy. Hardly any algae in my tank!