GW

From The Aquarium Wiki

GW is short for Green Water. A type of tiny single-celled algae which grows suspended in the water of aquarium tanks. This algae can rapidly multiple so that the water turns a dark green in colour.

A bad case of Green water can seriously reduce the levels of oxygen in the water and may out compete the bacteria in the filter for nitrogen, causing a reduction of the size of the bacteria colony. Therefore if the GW is removed, excessive ammonia may result as the biological filter can no longer cope.

[edit] Cause

This is usually caused by nutrients in the water (overfeeding?) and/or too much light.

[edit] Treatment

• Remove or reduce the light levels, often simply cutting down the time the build in lights are left on. Reduce light from outside the tank if light from a window falls on the tank.

• Perform a water change to dilute the algae.

• Add a media bag to your filter to remove the nutrient Phosphate from the water is commonly used to solve this problem. Though water changes must be carried out to remove the dying algae.

• Add plants to your tank to reduce excess nutrients from the water.

• Adding a UV device which kills the algae as it passes over the tube.

• Adding daphnia to the tank if there are no fish in it. They will eat the algae.

[edit] Links

• Green Water by The Krib