Why Is My Pond Water Brown? | Brown Pond Water Cure
Why is my pond water brown and Do you know of a brown pond water cure? was the heading of a recently received email from a subscriber to my free newsletter series who lives in warm and sunny Johannesburg, South Africa.
Mark wanted to know why he had brown pond water instead of having crystal clear pond water. I have received several similar requests and decided that this may serve as a good subject for a newsletter.
This Is What The Email Said ...
"Hi Sean
I live near to Johannesburg in South Africa and have a large 12,000 litre pond which is home to around 30 fish, including Koi, goldfish and Orfe.
I have the following equipment installed: A Hozelock Bioforce 12000 UVC filter and a Hozelock Titan 8000 pond pump. The Bioforce filter has a built in 13 Watt UVC light.
I also have a another waterfall pump that I use to power water to the top of a small water fall. I switch this off at night.
At present I have 2 large lily's living in my pond along with a few oxygenating plants.
Unfortunately I have a green / brown pond water problem. I cleaned the Bioforce filter today in the hope that this helps to clear up the pond water. I also changed the pond water last week.
Why is my water brown in my pond? Have you got any advice that may help me?
Regards
Mark"
This Is My Response To Mark...
"Hi Mark
How to clear brown pond water is a common problem encountered by pond keepers, particularly those with fish ponds. Excessive brown / green algae problems and pond sludge problems are amongst the most popular topics I am asked about by subscribers to my newsletter series.
When you say that you cleaned the filter does this include the fish pond filter material (biomedia)? If so then this is a bad thing to do as you have in essence removed many of the nitrifying bacteria that breakdown toxic ammonia.
As a result it will take a few weeks for the colony to reform in sufficient a number to be effective, at breaking down the toxic chemicals contained in fish waste.
If you meant that you have cleaned the filter and left the fish pond filter material alone then this is perfectly ok and it a good idea.
I see that you utilize 2 pumps; one for the filter and a different one for the waterfall. This is a good idea as running 2 Pond Pumps will actually save you money in electricity costs in the long term.
As long as you don't switch off the pump supplying the biofilter and allow the pump to run 24/7 then it is ok to switch off the other pump whenever you want to. A Pump Must Run 24/7 if it is supplying your bio-filter. If turned off for a few hours the nitrifying bacteria start to die off.
With regard to your brown water problem!
The brown water that you mention is more than likely as a result of excess suspended algae in your pond or too many insoluble organic compounds.
I notice that you say that your pond is 12,000 litres and that you have around 30 fish. Without actually knowing the size of the fish it is difficult to say if your pond is overstocked or not. I suspect that it may be though.
My Fish Loading Calculator will help you here ...
The more fish that you have the harder the workload placed upon your pond filter. The 30 fish certainly will do a good job of adding a lot of liquid and solid waste to the pond water. This contains ammonia which needs to be broken down by the nitrifying bacteria living in the filter.
The end result of this breaking down of ammonia and nitrite is nitrate, which acts as a fertilizer for plants and algae. Ponds with too much algae usually have green or brown pond water that tends to be murky. In really bad cases you can't see your fish and the excessive suspended algae may lead to fish fatalities due to oxygen starvation at night.
How to clear brown pond water the easy way with a UV Clarifier ...
A UV is the best green / brown pond water cure but it needs to be powerful enough and the flow rate of pond water through the unit mustn't be too fast.
If the flow rate is too fast then the algae isn't subjected to the UV light for long enough to effectively kill it.
You may need to install a second UV unit as I'm fairly confident that the 13 watt UV in the Bioforce 12000 UVC isn't powerful enough for the size of your pond, given the number of fish.
This is best connected between the biofilter and the pump. This way the biofilter can remove the dead algae as it is destroyed by the UV light. As the algae dies it clumps together.
Take a look at UVC Sterilizer Best For Clean Pond to read more about the benefits of UV lights.
If the brown pond water water is less obvious during your late autumn/winter, when there is less sunshine then excess algae is more than likely the cause of your problem.
The second reason for the brown pond water may because there are too many insoluble organic compounds in the water.
If there is a lot of sludge on the pond floor then your brown pond water problem may also be as a result of uneaten fish food, decaying vegetation, leaves etc then this will need to be removed using a Fish Pond Vacuum ... Cleaning fish sludge from ponds is important to prevent the opportunity for Fish Diseases to take hold.
A more permanent solution would be to install one or more bottom drains that would do a good sludge clearing job. This is advisable for large ponds such as yours, due to the level of waste.
An excellent UK product that ships world wide and does an excellent job of digesting sludge and keeping blanketweed at bay is Viresco
Excess debris increases the levels of nitrate, encouraging algae growth. It also prevents bacteria that live in the pond and breakdown these organic compounds from doing so effectively. This is especially a problem if your pond pH is less than 6.8 or higher than 8. It is always a good idea to test your pond water pH regularly using a suitable Pond Test Kit ...
Ideally you need to do this on a regular basis and at the same time of day. Take a look at the following article for more information relating to Why pH Is Hard To Control ...
Over feeding of fish is the most common cause of organic matter in the pond. When you feed your fish give them a Floating Fish Food and remove any remaining food after a few minutes. This will help to reduce the amount of insoluble organics in the pond.
Please be aware that fertilizing garden plants sometimes results in the fertilizer finding it's way into the pond water, thereby encouraging algae growth.
Hope this helps."
If you are looking for a green / brown pond water cure then take a look at these reliable and effective UV Lights for both small and large ponds. All models come with good warranties and are designed for in pond use.