Methods to Prevent Algae
Written by Aziz Dhanani   

In my quest to gain the knowledge necessary to set up a beautiful planted tank, it was evident in my search that many people gave up on planted tanks because of massive algae blooms and continuous algae issues.  The struggle to contain it and permanently eliminate algae was simply too much, and the would be aquascaper gives up on planted aquariums. Are algae wars magically selective for one person, and not another?  Of course not. Yet the truth remains, there are some who seem ideal algae aquarium growers, and there are those lushly planted aquascapes without a signal sign of algae. How does one keep an algae free aquarium?


It is generally agreed upon in the aquarium world that the best way to prevent and manage algae was through proper chemical fertilization of a planted tank including Carbon Dioxide (C02) injection.  When supplemented properly, these chemical injections promote a balance and stable tank that would not only facilitate healthy plant growth, but also create an inhospitable environment for algae.  However, with each aquarium being different from home to home there seems to be no true “proper” fertilization method that can achieve the same optimum nutrient balance needed to grow lush plants without the algae too.  I felt that there had to be other methods that could be simultaneously employed with the proper balance philosophy to help further deter algae.

The focus of this article is to recount my experiences in testing a combination of anti-algae measures.  These algae repulsion methods include using barley straw, Japanese Marismo Balls to absorb excess nutrients,  Eigera densa to ward against blue green algae, and disrupting algae growth with burst photo intensity and a variable photo period.  I will employ each of these methods to see if algae grows in my aquarium. Let’s  discuss the techniques.

1) Barley Straw Repulse Algae

According to a study by the   Integrated Approach to Crop Research Centre for Aquatic Plant Management the use of barley straw placed in a mesh in a pond or aquarium will release chemicals, specifically hydrogen peroxide as it decays under intense light.   Low levels of peroxide are said to be hinder and prevent algae growth.

2) Moss Ball Heavy Eaters 


Japanese Marimo  moss ball are high consumers of phosphates. As the moss ball grows, it out competes algae for phosphates and other nutrients. With limited phosphates available in the water column, algae is observed to have a difficult time gaining a foothold in the planted aquarium. 

3) Eigera densa Chemical Agent

Eigera densa is believed to secrete an antibiotic substance that prevents blue green algae (which is a type of bacteria that can dominate an aquarium).

4) Noon Burst Lighting

Aquarium plants are able to adjust to a four hour photo period of light, a few hour break, and then another four hour photo period. Algae on the other hand, has been observed by hobbyists to have an adverse reaction to a lunch time siesta of light.  The reasoning behind this has not been tested thoroughly enough to yield a concise result, however some believe aquarium plants are a higher organism and is able to adapted more readily to changing conditions.

Undergoing the Experiment

In July 2007 I experimented with these algae repulsion methods in a 10 gallon tank.  I first wrapped a piece of barley straw within a pantyhose mesh and placed it close to the light and filter out flow.  Secondly, to help consume excess nutrients, I decided to plant heavily from the start with marimo moss balls and Eigera densa.  Lastly, I configured the lighting which consisting of  30 total watts  for a noon burst type photo period.   One tube was timed to come on for 5 hours, with the other tube time to come on after 5 hours so that both tubes were on for a total of 10 hours.  No heater was used and the tank temperature was 25-29 degrees Celsius. I started off with Perpetual Perseveration System (PPS-Pro) fertilization scheme.  PH was 7.0.   

After four months of continuous fertilization using PPS-pro, signs of green spot and blue green algae appeared.  To combat the algae, I increased water changes to twice a week. I also began injecting CO2 through do-it-yourself C02 injection and a Hagen Submersible Filter to diffuse the CO2.  In less than, two weeks, the tank exploded with plant growth forcing me to do a major trim of the plants.

My Algae Repulsion Results

There were no indications of black beard algae, black brush algae, green dust algae, or diatoms for a while. But despite having the moss balls and other algae repulsion methods in place, blue green algae did appeared and green spot algae began taking over some plants.   In order to eliminate the blue green algae, I dosed erythromycin as per package directions and eventually it disappeared. 

After a while I noticed some plants began doing poorly like Ludwigia repens ‘rubin’ and Bacopa monnieri (money wort) but most plants remained healthy with a slow growth.  In an attempt to address plant growth issues that I felt stemmed from nutrient deficiencies, I decided to switch from PPS-Pro and try Tom Barr's Liquid Estimative Index (

At first, I dosed Seachem Flourish and calcium sulphate to supplement the already high nitrate and phosphate levels, and low iron levels in my tank. However this appeared to make no difference in plant growth, so I began dosing ¼ teaspoon of Kent Pro Plant and ¼ teaspoon of Seachem Iron on Monday, Wednesday and Friday; and 6 ml of  Tom Barr's Liquid EI solution combined with 1.25 ml Seachem Flourish Comprehensive once a week after 50% water change. This resulted in a major growth explosion in two weeks. 

Despite the algae repulsion methods, algae still appeared.  Ultimately this experiment confirms that finding the optimal fertilization scheme is key to  keeping  aquatic plants healthy.