Clear pond Water

There is a number of reasons that pond water appears cloudy, dirty or green. Also there, are number of easy solutions to fix the problem.

There is no reason that everyone can’t enjoy crystal clear pond water!

Quite often a brand new pond may be cloudy with clay silt from the rocks that have been used in the pond. Another common issue with a new pond is an algae bloom. Both problems are easily fixed.

An established pond may have problems with green water or a build up of sludge and sediment that is clouding the water again easily fixed.

Clear pond water

New Pond

Cloudy water

When i put in my front garden pond i used a lot of rocks. The rocks looked clean enough and i even rinsed them off with a hose. But when i started filling the pond it looked like a yellow mess! 

I didn’t want to waste water and pump it out so i left it in the hope it would settle. Over a week it did settle slightly but there was still a lot of suspended clay in the water.

After much umming and ahhhing i got a sump pump that can handle dirty water and pumped it all out onto the gardens. The sump pump was actually a great purchase as it is a very handy thing to have for any pond owner!

Once i pumped out all the dirty water and re filled it was crystal clear for about 2 weeks.

Solution: Remove dirty water and start again.

Algae bloom

I had beautiful clear water in my pond and then the algae started growing and growing and growing. I was in there pulling it out manually but that was a waste of time and effort.

You see new ponds don’t have an established colony of bacteria, which is essential to water health and crystal clear water. If you don’t know what I’m talking about check out this article- “A quick guide to the nitrogen cycle”. 

After some research i discovered that almost every new pond will go through a “green or algae” stage whilst the beneficial bacteria establish themselves.

Solution: Add beneficial bacteria as soon as possible. You can buy it in a bottle.

The problems for a new pond are easily fixed and no cause for worry. Eventually your pond will find a nice balance. The bacteria will colonise every nook and cranny within the pond and help keep the pond clean naturally.


Never top your pond up with water direct from the mains water supply! Mains water contains chlorine and this is incredibly harmful for your pond bacteria.

If you accidentally kill off your bacteria you’ll be back at the beginning as if it was a brand new pond. If you need to add mains water to your pond use a chlorine neutraliser on the tap water.

You can also let the water sit for a few days to allow the chlorine to evaporate. Other options include using tank water or filtered water. I know there’s a few companies that offer filters installed  right on the meter. If you’re filter removes chlorine you’ll be fine.

Green pond water

Established pond

Green water

It’s certainly not uncommon for a well established pond to turn green. There’s a simple explanation for this and it’s excess nutrients in the water! 

The green is caused by single celled algae. It’s a natural occurrence and it’s simply nature finding a balance. While it looks awful it’s in no way harmful to your fish and plants.

Fish actually love murky water, but excessive nutrients in the water can be a problem.

The most common cause is that the pond is overstocked with fish. Too many fish producing too much waste leading to too much nutrients. 

Solution: If you feel that the pond being overstocked with fish is the problem, the answer is simple send some out for sale or adoption.

But maybe you don’t want to part with any of your fish. Well you have a few options:

Clear pond water without reducing fish numbers

  1. Add more plants. Aquatic plants will consume the excess nutrients this should rob the single celled algae of its food source, eventually starving it. This is a good long term solution.
  2. Add a wetland or bog filter to the pond. These are easily my favourite kinds of filters!! They are completely natural. In short they work by slowing water flow, providing more areas for beneficial bacteria and extra plants. Click here to learn more. Again another brilliant long term solution.
  3. For a quick fix. You can remove manually using your pump and a fine cloth or filter pads. This will usually take a few days and many rinses off the cloth or filter pads. Another option is additives such as flocculants and algaecides. Simply follow the instructions on the bottle. The last option is installing a UV filter. These use light to kill the algae as it moves through the filter. These last options work but they only really mask the problem. There is still too many nutrients in the water. By all means use them but make sure to also add more plants and consider adding a wetland/big filter. Especially if you plan on keeping large numbers of fish in your pond.

Leaf debris

If the pond has no fish or you’re pretty sure it’s not overstocked it’s still the same problem, too high nutrients. But the cause is different.

Often the high nutrient load can be caused by decomposing material at the bottom of the pond. For example during autumn when heaps of leaves fall into the pond. The leaves break down releasing nutrients into the water.

Solution: Add a leaf net during autumn. This will capture most of the leaves and prevent the problem. This is fine for a small pond. Another option in a small pond is to net them out each day, it’s a pain in the bum but will prevent problems later.

For a larger pond you really should install a skimmer. These work by pulling water into them creating a current on the surface of the water. When the leaves fall in they get pulled by the current into the skimmer box. Then it’s simply a matter of removing the leaves from the skimmer basket.

This is also an option on a small pond. Just make sure it’s disguised so its not an eyesore.

You could also create a kind of DIY skimmer/collection point. To do this create a narrow channel and build it up with rocks to make the channel shallow. 

Place the pump on the other side of the channel. As the water is pulled through the narrow channel it will create a current. The leaves should bed pulled into the area where the pump is and can then be easily removed.

It’s quite hard to explain here’s a crudely drawn digram showing what my words cannot describe.

How a pond collection point works

Tea Coloured water

Sometimes with leaf debris the water will become cloudy or tea coloured. This is caused by tannins.

Tannins are a natural by product of the break down of plant material in liquid. In this case our ponds.

The tannins are harmless to fish and i actually quite like the tea colour. However some don’t and there is a couple of easy solutions.

Solution: You can use the skimmer/ collection points or leaf nets mentioned above to stop the leaves from settling in the pond in the first place.

A third option is incorporating activated carbon within your filtration system. The carbon acts like a sponge on very fine particles including tannins.

The only problem is carbon will require regular replacing. But it does work wonders in clearing the tannins.


Runoff from the garden or lawn can contribute to high nutrients loads and in turn green water. As the water moves over the garden or lawn it will pick up pieces of dirt, mulch, lawn clippings these all contain nutrients that will be released into the water as they break down.

Solution: Stop the runoff from entering the pond. This can be achieved by bunching up the liner and hiding with rocks. The physical barrier will force the water around the pond instead of into it. 

If you don’t have excess liner on the edges, create a small berm or shallow trench to channel water away from the pond. Again these physical barriers can be disguised with rock, plants and mulch. 

Dead animals

This is not usually an issue but has been known to happen in large ponds. Occasionally a rabbit or possum my fall into the pond if it cannot escape it drowns. 

Again it’s the decomposition that will release nutrients into the water. If it’s too much for the bacteria and pond plants to consume. Bam! you got green water.

Solution: The solution is easy, just make sure that animals that come down for a drink can escape the pond should they fall in. When designing a pond it’s important to have a beach area where the slope is gentle and animals can escape the water.

If you have an existing pond with steep banks incorporate some larger driftwood that can be used as a kinda bridge out of the water. Or some rocks to create a gentle slope or even some steps. It doesn’t matter as long as it looks good and will help the critters escape without clawing at your pond liner.

Cloudy water

Water that appears cloudy is caused by sediment within the water. This will be all the debris that has fallen into the pond- Leaves, Fish poo, Dust etc. As these things break down they become smaller and smaller and lighter and lighter. Once they are lighter than the water they will float.

There will always be some floating debris in a pond it’s when there’s heaps that you will notice it.

Solution: The solutions are many.  The more of the solutions you can incorporate the longer you should be able to go without any serious maintenance. 

  1. Create a bog or wetland filter. I bang on about these all the time i know. But that’s cause they are just brilliant at solving so many pond problems. In the case of sediment they will collect them instead of returning them to the water. If you haven’t already read this article. From time to time the sediment will need to be removed from the wetland/bog. 
  2. Using skimmers or collection points. The more debris you can remove from the pond before it breaks down the less sediment will be in the water- Simple! Click here for more information on how skimmers and collection points work.
  3. Avoid having bare earth around your pond. Bare ground when it’s dry will generate dust. Dust is just fine dirt particles. This in your pond will float around for ages! If the dust is from clay soils it can be really hard to remove as it never really settles to the bottom. Make sure to have plenty of plants around the pond. It looks better and should reduce the impacts of dust.
  4. Add more areas for beneficial bacteria. The bacteria is the engine room  of the pond. It’s a case of the more the merrier. Adding a bog/wetland filter will add heaps of surface area for these little guys and girls to colonise. Other options are adding bio balls, ceramic noodles ect to where the water comes into the pond. This maybe as waterfall, stream or fountain. 
  5. Adding activated to the filter. As i mentioned earlier the carbon will act as a sponge. These very fine particles will become trapped thus clearing the cloudy water. This is really only a viable option in smaller ponds as the carbon needs regular replacement.
Crystal clear pond water

If you can incorporate the top 4 and maintain a sensible fish stocking level you should never have a problem with cloudy or green water!

Hopefully this article has provided a solution or at least pointed you in the right direction, to being able to fix your particular problem.


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Hi, I'm Kev. My pond and water garden started with simple aquariums. I have created many ponds and water gardens around our home: Fish ponds, Aquaponic systems, grey-water wetlands and bog filters. My favourite topic is water filtration.

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