Continual green water. UV bulb new.

[Ian Butterfield]

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?

 

[dieselplower]

Do you have fish in there? What is the wattage of the bulb and the flow rate of the pump?

 

[Ian Butterfield]

Hello.

Thanks for replying.

I have 5 fish (2 goldfish, 2 Ghost Koi and 1 Golden Tench) in there the wattage is a Tropical Marine GT6 and the pump and filter box is correct for the size of pond.
When I first installed the pond, the equipment was 'sized' correctly by a pond pro.

 

[dieselplower]

Ok that doesn't help me help you. 5 fish seems lime too many. How big are they? What is the wattage of the UV bulb? What is the gph of the pump pushing water through the uv?

 

[Ian Butterfield]

I have had a look at the pump but the sticker to indicate the model number on it has worn away, but it is a Maximus (Lotus) Eco Pump. But it is the correct model for the water flow and size of pond.

The fish are as old as the pond and range from 4 inches to 10 inches.

Sorry for the lack of info but nothing has changed with the pond over the 12 years I have had it.

All the equipment is sized for the dimensions and water flow for the pond.

 

[dieselplower]

One thing has changed for sure... The size of the fish. 5 fish in 80 gallons is a lot. Especially when 2 of them are Koi. Bigger fish produce more ammonia than small fish. This ammonia turns into nitrite and nitrate. Algae "eat" those things, so as more of it is produced, the mire the algae thrive. I would day the size of the pump and filter needs to be based more on the fish load in this case. An 80 gallon pond with 5 large fish needs much more filtration than an 80 gallon pond with 5 small fish. Make sense?

 

[j.w]

Ian
One thing that changed after 12 yrs is your fish got bigger and make more poo now. Maybe put in some big poo eating plants like reed, rush or Yellow Flag Iris to suck it up?

 

[Ian Butterfield]

Thanks for all your responses.

I must admit, I am surprised that the greenness is down to the fish being too big for the pond.

Maybe it's time to give the fish away and get some smaller fish????

I do have YFIris in the pond but obviously not enough.

 

[j.w]

Hey dp we both posted up there at the same exact moment.

Can't be positive that it is the fish being too big. Don't know about UV's but maybe it will just take longer for it to work? Maybe try cutting down on how much you feed the fish and shading the pond w/something if it's in full sun. Algae loves sun and fish poo and rotting anything that makes food for it. More plants should help too. Would love to see your pond clear up for you
Also when I have a problem w/ too much fine mulm particles floating in my water that all isn't being caught up in my filter I like to use a plastic pot w/ quilt batting to run a hose from my pump to it to catch all that stuff. It works quite well but you have to keep stirring the water to raise the mulm off the bottom and keep hosing off the dirty batting and putting in clean. Could take days or weeks but it sure does help. I'm doing it right now to mine:

Really getting clearer each day!

 

[Ian Butterfield]

Thanks for the reply.

Slightly confused now if you are questioning the size of fish.

Like I said the pond is 12 years old and no problems up to this year. It has been gin clear for years.
Fish food carefully added, shade percentage is fine, amount and types of plants are fine. Filterbox working, pump constantly cleaned and free flowing and UV working with brand new bulb.

The only thing different is the fish have got slightly larger from last summer when it was last seen as gin clear.

 

[j.w]

If you say all is fine the algae is still there for some reason and it needs nutrients to feed on of some sort that must be in your pond. Get rid of what it likes and goodbye algae. You sure it's algae and not fine particles of detritus floating around? Is there any string algae or just the green look of soupy water type? Got any photos of the pond and water? Done any water tests?

 

[Ian Butterfield]

The water is green. And there is nothing out of the normal in terms of algae. Healthy amounts of aerating weed.
I'll try and get some images of the pond.

 

[BlueOrca]

The quilt batting does seem to catch a lot of fine debris for me as well. If your UV filter is killing the algae you still need to physically remove it to gain water clarity.

 

[dieselplower]

Ian the green water is floating algae. Also, whatever the aerating weed you have is, it consumes oxygen at night.

 

[Dave 54]

Hi ian in the 12 years your pond has been up and running have you ever cleaned the bottom of your pondof dead leaves detritus etc ?
If not can you get your hands on a pond Vacuum to give it a clean ?
On an average day how much do you feed your fish ?
Do you have an API pond test kit , if not your going to need one to test your water perameters ammonia, nitriite nitrate ph your going to have to do this on a weekly basis ?
Next what maintenance routine do you have in place with your pond when do you clean your filter out do partial water changes etc maintenance is a very important part of keeping yor pond and fish healthy diesilplower is correct when he says that algae will oxygenate your pond during the day but switches at night to produce Co2 as do all aquatic plants , can you get an airpump to put on your pond not one of the indoor variety but a propper pond air pump ?
The algae your experiancing is most probably due to a high level of nutrients in the water which is causing your problems at this time we'll need to get this down somewhat before your water will clear of algae .

Dave