The Light's On But The Water's Murky.

[Mehitabel]

Hi from a relative newbie.
I have a 750L pond with about 15 very small fish (they keep multiplying!). There's plenty of vegetation. The problem is that it's in full sun most of the day, so I have a constant battle with blanket-weed and algae. I have a Blagdon 2000 filter-cum-fountain with a UV light. It's always been effective in keeping the algae down. But since I re-started it after a winter break, the water's stayed green.
My question -- which doubtless shows my ignorance, but how else do you learn? - is: I've been assuming that because the light in the unit is shining brightly, its UV element must be working. So the cause of the persisting green water must be something else. Is that a wrong assumption, please? Should I replace the bulb?

 

[Hound Heaven]

Years ago I had a UV light for my pond and I remember having to replace the bulb, maybe annually? You may want to check with the manufacturer about your model.
Cheers
Also - we love seeing photos.

 

[YShahar]

Hi from a relative newbie.
I have a 750L pond with about 15 very small fish (they keep multiplying!). There's plenty of vegetation. The problem is that it's in full sun most of the day, so I have a constant battle with blanket-weed and algae. I have a Blagdon 2000 filter-cum-fountain with a UV light. It's always been effective in keeping the algae down. But since I re-started it after a winter break, the water's stayed green.
My question -- which doubtless shows my ignorance, but how else do you learn? - is: I've been assuming that because the light in the unit is shining brightly, its UV element must be working. So the cause of the persisting green water must be something else. Is that a wrong assumption, please? Should I replace the bulb?

Hi Mehitabel! Welcome from another relative newbie (how many years does it take for one not to be a newbie?)

I don't know the answer to the UV question, not having used one. But in the meantime, would you be able to put a shade cloth or umbrella over your pond? That might help you get ahead of the algae while you sort out the UV situation.

Another thing that might help is to increase the aeration in the pond. You could add another pump and use a scrap of liner to build a little stream to cycle water over rocks to help oxygenate the pond a bit more.

Once the plants higher up the evolutionary scale get going, they should begin to outcompete the algae and your water should clear up.

And yes, we love pics!

-Yael

 

[Mehitabel]

Also - we love seeing photos.

Hi. Thanks for the input. I didn't include photos because I didn't think anyone would be interested in a pic of a very ordinary small, murky pond.. But I'll remember for next time.

I don't know the answer to the UV question, not having used one. But in the meantime, would you be able to put a shade cloth or umbrella over your pond? That might help you get ahead of the algae while you sort out the UV situation.

Another thing that might help is to increase the aeration in the pond. You could add another pump and use a scrap of liner to build a little stream to cycle water over rocks to help oxygenate the pond a bit more.

Once the plants higher up the evolutionary scale get going, they should begin to outcompete the algae and your water should clear up.

I have a large wicker screen on the sunny side, which helps a lot. Also, I have a little solar aerator ball which fizzes away, as well as the Blagdon unit. I'll get a couple more, I think. The plants are pretty well established (I've had the pond some 12 years) but they've yet to out-compete the algae.. :-( Or, which is worse, the *********** blanket-weed!
Next plan: New bulb for the UV!