Mark Martin on Algae Control
Mark Martin, Director of Marine Ornamental Research at BZA, discusses algae control

I recently got an e-mail question from a customer about an algae outbreak in his aquarium. It sounded like he was doing everything right—his parameters looked good, and it sounded like his husbandry practices were sound. The one thing he didn't mention in his e-mail, however, was his lighting.

The two things you look at when battling algae is nutrients (which it looks like he was doing well with, unless the test kits are old or just not accurate) and light. Many times we find that parameters will look really good and nutrient levels will appear low but that is because all the nutrients are being utilized by the unwanted algae. Older bulbs can cause massive algae outbreaks because as the bulbs are burned they slowly shift to a different light spectrum in which algae thrives.

In a second e-mail from the same customer, he mentioned that he rinsed his food (for the fish) in RO water before feeding. This practice goes a long way in preventing unwanted things like preservatives from getting in the water. The number one preservative in frozen food is phosphate-based so, although his tests showed no phosphates, it’s possible the phosphates could be being used up by the algae quicker than he could test.

In order to get an immediate hold on the problem, I suggested he reduce his light cycle by a couple of hours. Depending on the type of lighting he has, I suggested a maximum of 6-8 hours. I also reminded him to be sure his bulbs had been replaced in the last nine months. In addition to adjusting the photoperiod, I suggested he start manually removing whatever algae he could and continue to test. My hunch was, if the problem was as bad as he said, as soon as he started removing algae, he would start testing higher nutrient levels.

Finally, I suggested he raise his calcium levels over 400 (I told him to hoot for 450). High calcium and ALK seem to prevent algae, especially hair algae, from growing out of control. The best way to increase calcium levels is with a calcium reactor or kalk reactor. Otherwise, I suggested he get the purest additives possible (the two that come to mind are from Tropic Marin and the new line from EcoSystem, as they both use pure calcium carbonate with no fillers or unneeded other stuff—a bunch of two part solutions have shown to actually increase algae growth.