Greenish water

[Alpravinosh]

Hi forum. I have a 1800 litre pond with a 6000l/h pump. In three I have 9 koi in there and three goldfish. I lately have noticed a decline in my water quality. It's becoming greenish. The water is still clear as in I can see my base very clearly, but that green tint to the pond is quiet disturbing. I have thought it may be due to the fact that the pond is overcrowded. My three largest koi are about 49 cm long and all my koi eat a lot of food. They eat a super premium diet which has a higher protein and fat content. So can I attribute my greenish water to the fact that my filter can't seem to handle the heavy fish load and there is a excess of nitrates, which algae and my aquatic plants are taking advantage of. Please do not that I do have a 36W UVC from OASE and worked remarkably well until now. I do know that the UV bulb is working well due to their small observation window and I can see that the bulb is free from debry. Please do help thank you.

 

[johan]

Small observation - these UV bulbs become inefficient after a year or so. Have you replaced yours recently?

best, Johan

 

[Alpravinosh]

Well thanks John, but my pond is only about 5 months old and my observation window tells me that my bulb is in good order.

 

[Alpravinosh]

Oh and did I forget to mention that I am from Malaysia, therefore I get 6 hours of non- stop sunshine on my pond.

 

[johan]

5 months should be fine - when bought they're good and you should get a full season out of them. Fyi, I have an observation window too - all it shows is a binary if the bulb is on or off. But it's the quality of the UV that matters, you can't tell this from the window. They don't go dark after a year

 

[johan]

Sounds like a simple problem of much fish waste from good diet and as you say, filters that need to man up . Sorry can't help, didn't know it was a new pond . Good luck .

 

[Priscilla]

Hi There! I have the same problem. My pond is only 1.5 years old. My UV used to control the green water perfectly and I had crystal clear water and thought I was doing a fantastic job. Unfortunately, at some point my bulb did die and it took me a while to figure out it was the bulb. My water went green and for the past 6 months I have not been able to clear it up. I did replace the bulb and its been up for several months now, but unable to clear the green water.

I live in the Caribbean and get a lot of sunlight down here.

Its been suggested that my fish are just getting bigger, as koi do and while my current filter and UV served me for smaller fish, the bigger they get the more waste they produce.

Good luck. I still don't know the answer to my situation, other than make my pond larger.