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Effective algae control - Sooner or later you're going to battle the green fuzzy monster. The good news is that algae can be kept under control simply and easily if you know a few basic secrets. Stop stressing out and start enjoying your tank!


It's an age old story, just add some water to a container and in due time you will see some form of algae take residence. Add a light source, throw in a few living creatures to provide waste material, and you're asking for thick green algae soup!

Algae has been on the planet from the very beginning and has lived opportunistically on nitrogen and phosphorus based compounds. Unfortunately these compounds are abundantly available in most fish tanks. To the aquarist, any type of algae that is out of control should be considered "bad." Algae that provides a source of food for small fish and other tank creatures -- while under control -- is not only "good" but welcome. Let's define "under control" as present but not harmful to plants and not so thick as to make it hard to see the contents of the tank. Think of algae under control as similar to a couple of weeds in the garden. If a few swipes of a magnet glass cleaner or hand-held scraper is the limit of your required maintenance, then your algae is well under control.

Identifying the type of algae you have is far less important than knowing how to gain the upper hand. Algae control is basically nutrient control, that's the bottom line, regardless of the type or color. Starve out algae and the game is over. Think of algae as a manifestation of excess nutrients in your tank. Covering the tank with dark plastic or the use of algaecides or special filtration (diatom, UV sterilization) are short term fixes that do not address the underlying excess nutrient problem.

Interestingly enough, algae can often times go through cycles as your tank matures and ages. Typically, early on in a tank's lifecycle a form of brown algae (actually diatoms) appears as smudgy brown sections on glass and decor. Algae eating fish such as Otocinclus or Plecostomus are known to greedily devour brown algae. Note that brown algae in a well established tank can be a sign of insufficient lighting. After brown algae, any number of algae types, separately or in combination, will try to opportunistically gain a foothold. Red algae isn't really red but ranges in color from gray to black. Red algae is typically brushy or beard like, growing in tufts on leaf edges. Green algae can run the gamut of little spots on the glass to thread like strands to pea-green soup. Blue-green algae is actually bacterial in nature, forms in slimy sheets and gives off a distinctive "musty" odor. There are no known fish that will eat blue-green algae due to it's somewhat toxic nature.

Here are some important tips to remember for effective algae control:

• Keep Nitrates as low as possible. Shoot for 10ppm or less if the fish load is not too high (25ppm and under is probably more realistic with heavier fish loads). Increase the frequency of water changes and cut back on feeding to achieve the desired results.
  
• Keep the lights on for no more than 12 hours a day. If it's a fish only tank use the light as sparingly as possible until the algae is under control. A typical light cycle should be 12 hours on and 12 hours off.
  
• Cut back on feeding. Maybe skip a day once a week to help improve water quality. Feed no more than your fish can eat in a few short minutes. Many more fish die due to overfeeding than those that actually starve to death.
  
• Discontinue any plant fertilizers. Often times the use of a new fertilizer will kick algae into high gear.
  
• Don't use water conditioners that contain plant extracts.
  
• Discontinue the use of cycling helper products (other than BioSpira from Marineland Labs), their effectiveness is questionable at best and they may even add nitrates that will feed your algae.
  
• Consider the use of phosphate absorbing beads if the previous things aren't helping much. Even a slightly elevated phosphate level can tip the scale in favor of algae.
  
• Watch out for pH buffers, many contain extra phosphates that may be feeding your algae as well.
  
• Add fast growing plants like Water Sprite to gobble up the excess nutrients and out compete the algae for food.
  
• Do not use algaecides. These can be harmful to plants & fish and do not address the cause of algae; excess nutrients.
  
• Use light bulbs with a color spectrum between 5000K to 6500K. This will help your plants get the type of light they need to out compete algae.
  
• Pick up some algae eaters:
  - Otocinclus are top notch clean up guys for small tanks. They will tirelessly scoot around the tank in search of bits of algae or leftover food. Otos do no harm to plants or driftwood and will readily consume brown and green spot algae. Stock Otos at the rate of one per 10 gallons of water for optimal results.
  - Ghost shrimp add a lot of interest to tanks with smaller peaceful community fish. They are top notch scavengers and will consume green thread algae if regular fish food becomes less plentiful. Some people report that they even eat red algae! Other scavengers like Corydoras catfish help keep uneaten food to a minimum as well. Stock scavengers including ghost shrimp at the rate of two per 10 gallons of water.
  - Siamese Algae Eaters (SAE) are the only fish known to eat red algae! They can get pretty aggressive and grow too large for small tanks, so beware.
  - Chinese Algae Eaters are not recommended as they grow large and become aggressive. To make matters worse they aren't even good algae eaters!
  - Snails are moderately good algae consumers as long as they are small. Larger snails will prefer fish food and your prized plants. Note that larger snails will damage your plants while rasping for algae.
  - Plecostomus are great algae eaters for larger tanks containing aggressive fish. They do grow large and will damage plants as they get bigger. Plecos require driftwood to munch on.

In closing, put your cleanup crew in place, keep an eye on excess nutrients, use the proper color spectrum & lighting duration and you should be well on your way to effective algae control.