Water Turning Green in a Fish Tank

When you put ​tap water in a ​fish tank it ​shouldn't ​turn it green ​in a couple of ​days but this ​happens to my ​water, as seen ​in the picture. ​

The water ​tastes slightly ​tangy, which ​means it's ​most likely ​acidic. Maybe ​acidic enough ​to strip pipes? ​Because it also ​tastes slightly ​metallic. ​

I think the ​house is on the ​end of the ​distribution ​system because ​there is little ​to no chlorine ​in the water. ​

it is ​also ​possible that ​there is an ​overdosing of ​sodium ​bisulfite, ​which could be ​the reason for ​little to no ​chlorine. ​

Would there be ​any other ​reason as to ​why the water ​would turn a ​fish tank green?​

Taxonomy

• Treatment
• Chemical Treatment
• Water Treatment & Control
• Chlorination
• Water Supply
• Algae
• Algae Treatment

5 Answers

1. You can use dry barley straws to reduce algae. Soak them in affected water for couple of days. 

2. Dear Richard,

   Water turning green is a result of the growth of algea. This will happen when your water is too much exposed to sunlight. I also see that there are no plants in the water, it is advisable to put plants in your aquarium. Before putting plants in the aquarium, you can destroy the algue in the water with an UV-C unit, so the biological environment of the aqaurium is more stablized.  

   You can check on our website how UV-C works and which unit suits best for your aquarium. If you have any questions, please feel free to contact me. 

   www.vgebv.nl 

3. Have you tested the source water for N and P? Most municipal supplied water does have a low level of each, but still sufficient to support a growth of phytoplankton.

4. Water Turning Green in a Fish Tank

5. Dear Richard,

   Most likely this green color and the turbidity are caused by (micro)algae. You can check this with a simple microscope.

   If so, then this indicates that there are plenty of nutrients in the water including phosphorus inducing the algae growth along with the white light.

   The metallic taste and acidity probably result from corrosion upstream in your water supply.

   Apparently there is not too much sodium bisulfite in your fish tank as the fish seem to survive The aeration enables the  oxidation of bisulfite to sulfate.

   Perhaps it is time to clean your fish tank and filter system. If needed replace the filter cartridge as well.

   Regards,

   Bruno