Pond algae problems are serious. Conquer it | Use UVC filters

Koi and goldfish dying in green algae pond ... need UV and biofilter

Hello,

My dad has a very large goldfish pond that is about 20+ years old. Late last summer he started losing his biggest koi one by one. This year now that the weather is getting warmer again he is started to lose his biggest gold fish (maybe 4 per day). His pond is 5 1/2 feet deep, 6 feet wide and 6 feet across. He has a lot of plants, but it appears to me he also has a lot of algae buildup. His water has a dark green tint to it. He leaves his water falls running 24/7, but the goldfish are still hanging around the top of the water. Some are even raising their heads an inch above the water for oxygen. There is obviously an oxygen problem in the water. My question is....do you think it is the algae? Or...could it be the waste and debris at the bottom of the pond? He tried cleaning the "gunk" out a few years ago by hand....but it was a major - stinky task. He doesn't have much money to spend on an expensive remedy, so I was hoping there may be something else we can do.

Should we buy the algae killer stuff that turns your pond blue? Would that help? He had the water tested and there is a slight raise in ammonia (which I know can kill the fish too).....any advice you can give would be greatly appreciated.

I think he needs to clean the stuff out of the bottom, but what's the easiest way? and killing the algae? What's recommended?

Thanks,

Shannon

Yes you have a major algae problem by sounds of it ... the algae compete with fish for oxygen especially overnight. Read this article here
http://www.practical-water-gardens.com/pyjamas/article010co2.htm

Summary of article ... Think of your pond as breathing in oxygen during the day and breathing out carbon dioxide at night
Carbon dioxide pond problems can be controlled by waterfalls, aeration and uv lights. Carbon dioxide in pond water results from a number of sources including:
1. waste products decaying at the bottom of the pond

2. respiration by pond inhabitants .... fish, insects, plants, algae

Of course all of us think first and foremost of oxygen in pond water as being essential and of course this is very true. Carbon dioxide is also of critical importance. Oxygen and carbon dioxide also work in concert with each other.

In simple terms as carbon dioxide levels increase in a pond then oxygen levels tend to decrease. This follows a natural pattern as can be seen in the sketch. Here you can see that from dawn to dusk (daytime) oxygen levels in pond increase and decrease again from dusk to dawn (night). Carbon dioxide concentrations in water act in reverse - falling during daylight hours and rising during the night. Oxygen levels are at their highest at dusk and carbon dioxide levels are highest at dawn.

Beware algae blooms in ponds ... this is what is happening in Sharron's dad's pond

Let's equate this to what living organisms do in the pond. Think of the flora and fauna as exhaling carbon dioxide while inhaling oxygen during the night.
From this you will agree that dawn is the critical time in a pond. Often people wake up to find dead fish and wondered what happened. Such deaths could be associated with very low oxygen levels coinciding with high carbon dioxide levels. When ponds are full of suspended algae such problems can arise.
If there is a very small amount of algae bloom in the pond then you will find oxygen and carbon dioxide levels will not change significantly between early morning and late afternoon. On the other hand dense pea soup type water will show very significant variations.

Seasonal Impacts upon carbon dioxide problems

The first thing to realise is that oxygen concentrations are highest in winter because water is cooler. This means the concentration of oxygen can be higher. Because oxygen concentrations are high the oxygen reserve is not depleted so quickly during the night. Plant and animal life has also slowed down significantly.

On occasions fish in ponds with no fountains or waterfalls may look listless in winter due to carbon dioxide levels being excessive but this is normally associated with a long run of calm dull days - in these circumstances there is no natural wave action to allow oxygen to be transferred to the water. The problem quickly sorts itself out when windy and bright weather returns.

In summer water can hold much less oxygen and the animal and plant life (algae) is also thriving due to higher temperatures along with more nutrients in the water associated with feeding fish. The living organisms are therefore emitting more carbon dioxide in a situation of potentially disastrously low oxygen levels . Fish then die from suffocation.

Sharon

You need a biofilter and UV urgently I suggest you take look here

http://www.practical-water-gardens.com/sitedirectory4.htmor use links to right on this page

UV kills algae 100% effectively and results in clear water when sized properly

No fish pond should be without biofilter and you MUST clean out the gunk on the bottom of the pond ... if it stinks to you imagine how the fish feel living in and around the mess 24 hours per day

By the way goldfish are far more tolerant of poor water conditions than koi and this is reason probably for koi dying last year and goldfish this year. Of course fish have also put weight on so they are also producing more nutrients making need for biofilter even more important

Summertime, and blanketweed or string or filamentous algae

First of all thanks to Robin for the effort he put into recording what he actually saw happening in his pond. Robin in Germany wrote to me with his pond problem which is an extreme one in my opinion and well worthy of sharing with all other readers worldwide, owing to the apparent severity and rate of growth of what I believe to be a blanketweed problem . Robin sent me a photo and I can only compare what I saw to "Triffids" ... all those people less than about 50 probably won't understand this term which refers to an out of control plant species in a book called "The Day Of The Triffids" by John Wyndham

By the way UV has no impact whatsoever on blanketweed because UV only effects what is circulated over the UV source.

Here's Robin's letter and my reply which is based upon the assumption the problem is blanketweed (in the first letter Robin provided detailed observational details) ...

Dear Tony,

Greetings from Germany.

It has been almost 3 weeks since my last letter, and I wanted to update you on what I have done. Directly after my last letter we had another cold front move in, and the temperatures at night dipped under freezing and with cloudy days, the high temp was 10 or below. The water temp in the pond cooled to 8 grad c. The junk floating in the water all settled to the bottom, and the water remained clear and not dirty (suspended objects) for several days. I would run to the pond when the sun shined even for just a few minutes, and observe what was happening.

When the sun shined it would warm the PLASTIC areas that were not covered with sand or rocks, and the tiny hair like whatever (a word fails me) would start growing immediately (you can see that in the picture). Actually it is dead Algae that is just sticking together. When the water warms (late afternoon) these hair collections will shoot to the surface like being shot out of a gun and continue to collect together. (That is the stuff floating in the picture). The picture is HIGHLY magnified (zoomed with a polarized filter so you could see exactly what I am talking about in reality the stuff is very small and hair like).

The nights are still cool (5-7 degrees) and by morning the water would be settled and clear. Then as the sun comes out and the plastic warms, the entire process starts over, and by late afternoon the surface looks like a stopped up toilet, and the hairs that have not reached the surface are suspended giving the water a very green color (NOT like green pea soup). The water is clear, but dirty!

It is necessary to clean the filters 2 times each day, or they clog up like a green mud, and I have had to take the pump apart twice to clean it out (since writing last).

I am trying my best not to change the water, as I would like to find a solution to this problem.

Observation These hairs form only on the plastic area, not on the sandy areas. However, during the evening settling process, this debris covers everything!! My lily pads (are still trying to grow out of the winter dormant stage and are still totally under the surface) leaves are so covered with this debris that 3 plants have died, even after I have tried to gently brush this stuff off the once large leaves. This debris of dead Algae has killed the water grass, and only a few plants are doing well. My bigger fish swim (chase each other) during the day, and come close to the bare plastic areas and stir the debris, which goes suspended through out the entire pond. Even if I drained the water and replaced it, I dont know how I would get the remaining debris out without making a bigger mess than I now have. For several days in a row I have run fresh water in the pond, forcing it to overflow, and it takes the floating debris out, but does very little for the suspended stuff.

The picture was taken today, and you can see that very little forward progress has been made. The UV light is new and has been working for about 8 days. My pump, as I remember from the box, pumps around 7,000 liters and the pond is only 14,000 liters. It should have easily removed the suspended debris, but it has not. A LOT gets caught in the hard particle portion of my filters, but if I do not wash them at least 2 times each day, then the filters go to the overflow and the water just runs unfiltered back into the pond. I did not have this problem last year when the pond was cement only. Could something be wrong with the plastic liner?

Idea (for your approval). When I bought the liner, I also bought a liter of glue in anticipation of future repairs. What if I let the water level down below the bare plastic area paint this glue on the bare plastic, and immediately throw sand on it. Then (I think) the sand would stick, and the problem of too slippery would be solved. I also think that the debris forms and shoots up from the bare plastic areas, because the black plastic warms up much quicker than the protected plastic (covered with sand or rocks).

Other than that, I am about at wits end, and have no other ideas except to slow the water flow into the filter and waterfall, giving the light a little more time to work (although I think it is doing the job ok). As always, thank you for your time and advice.

Your friend,

Robin

Dear Robin

I cannot find the reference I had to University guy ... so here are a few more comments from me

I do really think your problem is blanketweed. Consider the following aspects of blanketweed, also called filamentous algae or string algae (under microscope you see long chains of single cells all joined together....

Grows rapidly and outcompetes other algae and hence water is clear ... because the string algae does not have roots it can only source its food from dissolved nutrients and it needs a lot to grow in abundance

1. During daytime blanketweed grows by virtue of photosynthesis and attaches itself to any substrate (eg your liner) in long strands ... ie liner is acting as anchoring point for string algae and the anchor is by its nature very weak because blanketweed does not have roots
2. During daylight hours and especially as temp warms up and sun comes out oxygen is produced ... sun + warm water = more oxygen + faster growth of blanketweed. The blanketweed "string" is thus floated up to the surface where it dies and forms clumps of green yellow algae. The clumps float because of trapped oxygen. Once oxygen has been lost then some algae may sink
3. Your smooth liner may be bad at providing a more sustainable anchor ... unlike plants which also get invaded by the algae (plants are a much better anchor point) and from which the stings do not easily break away. The result of this is that in time the string algae causes the death "by strangualtion" as it were of the plant
4. Fundamental cause of big blanketweed problem is nutrient excess as mentioned previously. Can you collect rainwater from roof and gradually use this to replenish pond water?
5. Shallow water favours blanketweed formation because of tendency to warm up and high sunlight penetration. Do you see formation at bottom of pond or is there more on sides ... ie closer to surface where more light enters
6. Putting lot more plants into pond will help by converting nutrients and also forming a barrier to sunlight in parts of pond
7. You will know from fly-fishing that alkaline waters (chalk streams) favour algae growth ... is your pond alkaline? Under these conditions blanketweed growth can really accelerate.
8. Whatever you can do to reduce sunlight penetration (hence more plants) will help ... days in Europe also getting much longer
9. If you continually add high nutrient water from your borehole this will worsen your problem Bear this in mind ... stop continuous flow into pond and rely upon biofilter
10. Let me know what happens with time. Any feedback I might get from UK I will forward to you .... no simple or permanent cure for blanketweed and if barley straw works it is not an instant short term cure. If you read report I sent you will see they are approaching problem as a 3 year experiment

Important Fish Pond & Water Garden Articles to View...

Learn how to choose a fish pond pump ... pond pumps circulate oxygen enriched water to keep fish and pond filter bacteria alive. Fish pond filters make sure water gardens remain clean and healthy for you and the pond fish. Learn how to choose a UV light for your fish pond... UV sterilizers make sure backyard ponds remain crystal clear and green algae free. Water garden plants help to keep garden ponds in balance by removing nutrients on which pond algae feed. Most fish ponds and water gardens are built from flexible pond liner. If your fish pond ever suffers from blanketweed this is the page to view.

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