Continual green water. UV bulb new.

[Mucky_Waters]

How often do you do water changes?
Routine water changes help remove, not only, extra nitrates (nutrients), but also any other suspended solids that effect water clarity, and also helps stabilize the PH, water hardness, and other qualities of the water. (providing the source water is reliably stable).
I prefer doing a constant drip type water change, which is having a constant steady 24/7 drip into the pond and letting it overflow. This method is safer and easier then doing manual water changes.

 

[LarryM]

Hello.

My pond (about 12 years old) has green water at the moment as I switched off the UV cus the bulb got too weak.

I have now replaced it (few days ago) but the green water remains. No signs of clearing.

It's a typical small family pond, nothing special. About 320 litres, with a UV bulb and filter box.

Obviously I have checked the equipment and all is good.

Any ideas please?

Since it's such a small pond, I would think a couple 50% water changes would do the trick.

 

[Ian Butterfield]

Thank you all for your replies.....interesting reading.
I will answer some points thrown up.
The set up is 12 years old and regularly cleaned. Even had to reline the pond a few years ago due to puncture. Water is regularly topped up. Nothing has been added or taken away (only the fish getting bigger of course) and there is less fish in there than the beginning. We let the population reduce as we were going to move but didn't happen. I just don' tunderstand how a set up can work perfectly to a gin clear level for 10 or so years then all of a sudden go to this.
I will do a 50% drai and refill and see what' what.
Thank you.

 

[Ian Butterfield]

I wrote to Tropical Marine Centre (the UV bulb manufacturer) about my query and just had a reply back from them:-

Thank you for your enquiry.
- To speed up the process of clearing your pond, please put some filter floss (which looks like cotton wool) into your pond filter as the tiny dead algae particles are so small that they will slip straight through most filter sponges, even the fine ones!
- However, you will need to leave the UV running for a total of 6 weeks after fitting a new lamp and cleaning the quartz as the sudden hot spell might be to blame!
N.B It can take a ‘healthy’ UV up to six weeks to clear a pond.

 

[dieselplower]

That's interesting. Mine takes 2 or 3 days.

 

[Ian Butterfield]

I must admit I do find that info a bit strange. Whenever I have replaced my UV bulbs it's only taken between 1&1/2 and 3 days to clear. Which is why I have queried the time on this occasion.

 

[dieselplower]

Ian let me ask you this, how clear was the housing that the bulb goes into? When I replaced my UV bulb, I found that the housing, which I believe is made of quartz, had a decent layer of build up on it. Calcium from my very hard water maybe. I have read on reputable sites that if the housing has a build up on it, the light is not nearly as effective because it does not penetrate the build up very well, and as such, has less of an effect on the algae.

 

[Ian Butterfield]

Thanks for asking. Before I replaced the bulb, I electrically disconnected the filter, took it all apart and gave it a good clean. The quartz was removed and also given a good clean. Everything was put back and new bulb in. That was over a week ago now.
The quartz has always been regularly cleaned.

 

[Ian Butterfield]

Yesterday, I did a 50/50 water swap, thoroughly cleaned out the filter box, checked all plants and did an overall MOT to the pond.
Today the water is gin clear. So we'll see how long it lasts.

Thank you to all who have advised.

 

[DoDad]

Can you see the light from the bulb?

 

[Ian Butterfield]

Yes all equipment is working okay.

 

[Carol Wilson]

According to me, the reason is overloading of fish into this small pond. and changes in the chemical composition of pond water, then, algae grows.

 

[Ian Butterfield]

Hello all.

The update is this. It's about 10 ten days since the 50/50 water swap and since then the water has remained gin clear.

This fabulous news, so a big thanks to all who chipped in with their experience and knowledge to allow my fish to see where they are going!

BTW....my stock contains 4 fish, 1 Golden Tench 6", 1 Goldfish 6" and 2 larger than first thought Ghost Koi at 16"! I did have 13 in there a few years ago, but natural death, cats and a Heron has left to what it is today.

Thanks,

 

[Mucky_Waters]

Hello all.

The update is this. It's about 10 ten days since the 50/50 water swap and since then the water has remained gin clear.

This fabulous news, so a big thanks to all who chipped in with their experience and knowledge to allow my fish to see where they are going!
Thanks,

Since I was the first one in this thread to suggest a water change to you, I will say you are welcome.
Periodic water changes seem to be at the top of the list of most over looked maintenance routines for new ponders unless they have a history of successfully keeping aquarium fish where routine water changes is a lot more important. At least with pond most people can't help getting some naturally assisted water changes through natural a processes (rain). Problem with depending on rain is if you live in a dry climate like mine you don't get nearly enough to flush your pond properly, not to mention rain tends to carry a lot of free nitrogen with it, which can actually boost algae growth. Also rain water is often very acid when it comes down, which, if you get a lot of it all at once, can be very stressful on fish. The other thing is, rain water is very low KH, and if you relied on it for all your water changes you could end up with very PH unstable water in your pond, which again could be very stressful (if not deadly) on your fish. There are ways to compensate that, but it's much easier to just do routine water changes with a water source that is already higher in KH.
A 50/50 water change is a pretty big water change. You'd be better of doing smaller, more frequent water changes, and if you can, try to remove or vacuum up the sludgy, nutrient rich, water from the bottom of your pond and replace it with water that has previously had time to sit and de-chlorinate for a day or two. Use the nutrient rich sludgy water you sucked out of your pond to water your garden or something.

 

[Ian Butterfield]

In actual fact I did a larger percentage water change and all is well. As for the sludge, well there basically isn't any at the bottom of the pond.
Pond skaters, Damsel flies and many other creatures are happy with the new clear!