Aquarium algae, like any plant, require the following to thrive: Oxygen, light, water and nutrients (primarily nitrate).
How to control aquarium algae and clear green water:
Because fish depend on it, we have little to no control over specific levels of oxygen and water.
Therefore light and nitrates need to be controlled and manipulated in order to control and prevent algae from overtaking the fish tank.
These are our two primary tools for algae control and algae prevention:
1. Controlling and adjusting the aquarium lighting:
Algae are photosynthetic and use light to produce energy (sugar) for food. The following measures, alone or in combination, can reduce chances of an algae outbreak:
- Avoid direct sunlight. If the aquarium is setup in a location that receives direct sunlight consider lowering a blind when needed. Setting up the fish tank in a location to avoid direct sun light is preferable
- Limit the photoperiod (lighting duration); 6-8 hours depending on the amount of light the room provides. This can be shortened considerably when combating green aquarium water or an algae bloom
- Replace light bulbs every 6 – 9 months based on the photoperiod. The color spectrum changes in aging bulbs making the light produced more favorable for algae growth. This is not usually visible to the eye
- Avoid intense light (unless required for a planted aquarium or reef tank)
2. Nutrient control helps control and prevent aquarium algae:
Nutrients that should be controlled include nitrates, dissolved organics, carbon, CO2, minerals, phosphates, etc. all of which are key ingredients for plant and algae growth.
- Nitrate levels should be kept below 5 ppm (the lower the better)
- CO2 levels can be kept low by aerating the water (surface agitation)
- Maintain phosphate levels below .05 ppm (undetectable)
- Do not overfeed the fish/ aquarium
- Do not overstock the aquarium
- Maintain the aquarium every 2 weeks (water change/ vacuuming substrate to remove dissolved organics)
- Introduce bottom feeders to remove debris if possible
The bottom-line about algae growth in the aquarium:
The more adjustments the aquarium requires to bring it into balance, the more likely algae will become a real problem.
While all of the above measures will lead to a healthier, more balanced aquarium, perhaps the most important assets any fish keeper can have are patients and understanding.
When we are able to diagnose the problem, apply the required adjustments, and exercise the needed patience, we are on our way to a biologically balanced aquarium.