Help!

[LHB]

I need advice. I have a 10 year old natural bottom pond, approximately 26,000 gallons, sited in partial sun. In it I have about 15 large (12inch) Koi and 20 4-6 inch koi as well as a variety of fish babies, toads and frogs in it which were introduced last year. I have had water hyacinths and lettuce in the pond every year. The pond is from channeled rainwater from my roof. It was always crystal clear until 2 years ago (before fish). Now the water is greenish brown and cloudy in the pond but a gallon sample has no visible algae or sediment in it. It's clear but slightly green. Can anyone give me advice on a pump, UV and bio filters to make my water clear again? Or any advice on what my problem is?

 

[Mmathis]

Welcome! No particular advice regarding filters, etc., but I can hazard a guess as to why the water quality has changed. Before you had fish, you didn't have any waste products. Now you have the fish. Fish waste = plant food. Sounds like you have algae that's making the water green,

 

[LHB]

Thanks but the problem started the year or maybe 2
before the fish were put in. They just came in August of last year and the pond has been for 2-3 years. According to the koi guy a 26,000 gallon pond should easily support the number of fish that I have,

 

[Meyer Jordan]

Earthen bottom pond + Koi = turbid water. Koi are, by nature, bottom-feeders. The root around in the bottom of the pond looking for tid-bits, stirring up the bottom soil and sediment in the process.
You don't indicate what other aquatic plantings you have in the pond. Apparently not enough or you would not have perpetual green water. Are you getting any surface run-off in the pond?
Rainwater is not clean. It can contain a considerable amount of Nitrate, especially during a thunderstorm.
Have you tested the water lately? If not, do so. This will give you a clearer picture of exactly what you are dealing with.
With an adequate number of aquatic plants, the green (algae) should dissipate naturally. The turbidity problem you will have to live with. This is why Carp (Koi) in natural waterways are considered a nuisance specie in most parts of the world

 

[LHB]

Thanks for the reply. When I take off a large gallon + sample and let it sit there is no visible algae or silt after 2 weeks

.
The water looks transparent except for being faintly green. This problem started 1-2 years before I got the fish.

As you can see I had lots of water hyacinths, water lettuce, papyrus, water hibiscus, 2 huge pots of elephant ears. The surface of the pond was almost covered by August. It was treated with barley pellets, narley bails and 2 shocks of fish friendly algaecide with no results at all. Visibility is about 3 inches deep. Pond is about 3 feet deep at the middle. I haven't run any water tests yet and yes the lawn slopes down to the pond so there would be some run-off. Is there any water testing place that you know of specific to fish ponds? Thanks for your help

 

[LHB]

Welcome! No particular advice regarding filters, etc., but I can hazard a guess as to why the water quality has changed. Before you had fish, you didn't have any waste products. Now you have the fish. Fish waste = plant food. Sounds like you have algae that's making the water green,

Green came about 2 years before the fish. Fish are recent, last August.

 

[MitchM]

For a pond that size, I would suggest installing a bog as a filter instead of spending money on mechanical and UV filtration.
Have you had a look through the bog building thread in the construction section and had a look at addy1's pond?
She is in Maryland as well.

https://www.gardenpondforum.com/threads/pond-in-progress-started-4-21-10.4302/

https://www.gardenpondforum.com/threads/bog-building.6894/

 

[Meyer Jordan]

Couple of additional questions. Does this level of 'green' remain consistant all through the warm months? Have you had any occurrence of floating algae?
You can buy a basic test kit on line, but I would recommend more comprehensive lab tests be done not only on the water but also the soil at the bottom of the pond.
Check with your county extension office. They should know of a university or private lab that can conduct these tests for you. A quick search provided this lab-http://www.chesapeakeenvironmentallab.com/

In a true earth-bottom pond, such as yours, a Spring algae bloom is not only to be expected but also is desired for it is the beginning of re-establishing the natural aquatic food chain. The algae serve as a food source for various zoo-plankton which, in turn, serve as a natural food source for other larger organisms, including fish. The algae, under normal circumstances, will almost completely disappear as temperatures rise. It should not, however, completely disappear because the food chain needs to be sustained all through the warmer months.

 

[LHB]

Couple of additional questions. Does this level of 'green' remain consistant all through the warm months? Have you had any occurrence of floating algae?
You can buy a basic test kit on line, but I would recommend more comprehensive lab tests be done not only on the water but also the soil at the bottom of the pond.
Check with your county extension office. They should know of a university or private lab that can conduct these tests for you. A quick search provided this lab-http://www.chesapeakeenvironmentallab.com/

In a true earth-bottom pond, such as yours, a Spring algae bloom is not only to be expected but also is desired for it is the beginning of re-establishing the natural aquatic food chain. The algae serve as a food source for various zoo-plankton which, in turn, serve as a natural food source for other larger organisms, including fish. The algae, under normal circumstances, will almost completely disappear as temperatures rise. It should not, however, completely disappear because the food chain needs to be sustained all through the warmer months.

Yes color now remains consistent through out the Summer, Fall and even this exceptionally cold Winter when I expected it to clear, it did not. 2-3 years ago I had a non-slippery stringy algae which appeared not to be attached to the bottom but didn't really float either. It seemed to be about 6 inches below the surface. My grandkids called it "mermaid's hair" and the description was perfect. It was very fine, like a thin net about 12 inches wide. It could be wound around your hand like collecting cotton candy. That algae suddenly appeared after the pond was about 6 years old. It came for 2 summers even after I pulled it all out and has not returned since the fish were introduced. Thank you for the extension office suggestion, that sounds perfect. Here's a photo of the "mermaid's hair". It was growing faster than I could pull it out.

 

[LHB]

For a pond that size, I would suggest installing a bog as a filter instead of spending money on mechanical and UV filtration.
Have you had a look through the bog building thread in the construction section and had a look at addy1's pond?
She is in Maryland as well.

https://www.gardenpondforum.com/threads/pond-in-progress-started-4-21-10.4302/

https://www.gardenpondforum.com/threads/bog-building.6894/

Thanks for the suggestion.I am a complete pond novice so I don't know what a bog filter is but I will read it.

 

[Meyer Jordan]

Yes color now remains consistent through out the Summer, Fall and even this exceptionally cold Winter when I expected it to clear, it did not. 2-3 years ago I had a non-slippery stringy algae which appeared not to be attached to the bottom but didn't really float either. It seemed to be about 6 inches below the surface. My grandkids called it "mermaid's hair" and the description was perfect. It was very fine, like a thin net about 12 inches wide. It could be wound around your hand like collecting cotton candy. That algae suddenly appeared after the pond was about 6 years old. It came for 2 summers even after I pulled it all out and has not returned since the fish were introduced. Thank you for the extension office suggestion, that sounds perfect. Here's a photo of the "mermaid's hair". It was growing faster than I could pull it out.
View attachment 79427

Is that concrete edging around the pond perimeter? Not doubting your word, but are you sure that this an earthen-bottom pond?

The 'Mermaid's Hair' is a form of floating algae that I was asking about.
Right now any diagnosis would be conjecture. Once you obtain the test results we can narrow the focus on causes and remedy options.

 

[LHB]

Is that concrete edging around the pond perimeter? Not doubting your word, but are you sure that this an earthen-bottom pond?

The 'Mermaid's Hair' is a form of floating algae that I was asking about.
Right now any diagnosis would be conjecture. Once you obtain the test results we can narrow the focus on causes and remedy options.

No, not concrete edging just some sand that popped up as a layer in the clay when digging. Not sure why the weeds wouldn't grow over the edge. Absolutely sure of the pond bottom. I built this house and was required by the county to contain roof runoff in this precise size pond. I watched the dig. I'll get the testing done ASAP. The only other things I haven't mentioned are a huge gabian basket retaining wall about 15 feet tall and 10 varieties of frogs and toads identified so far. About 80 decibels of lovely noise each day.

 

[addy1]

I get string in my small slow flow ponds, never any green water even at spring start up. I pull my external pump in the fall reinstall in the spring. It is a little murky in the spring when first starting it up, then it clears right up.

My bog is around 1/4-1/3 the size of the pond, full of plants.

 

[LHB]

I run my pond fountain all year round.

 

[southern_guy]

Would an over abundance of built up nutrients in the water cause this? Example mud bottom /plant die off in fall /fish waste