Is your garden pond water gross and murky like pea soup instead of sparkling, clear the way it should be? I came up with this simple, fast method for cleaning the water after trying numerous, slower methods like traditional bio filters. As you know, when the problem is really bad, you’ll never get ahead of the gunk without direct action first.
I’ll show you how it’s done and—good news—it’s simple to set up and the water often clears within a couple of hours.
I originally posted this method for clearing murky pond water over ten years ago and have received hundreds of testimonials from happy pond owners. You can see an older version of this information here.
Is Your Pond Gross and Murky Like This?
Whether it’s slightly green or thick like pea soup, where you can’t see the bottom and only get glimpses of the fish, this quick cleaning method for pond water may work for you.
While, I’ve only tested it on ponds smaller than 1000 gallons, it may work on larger ponds if you have the appropriate strength of recirculating pump and you allow enough time for all of the water to be filtered. In other words, the larger the pond and the grosser the water, the longer it will probably take.
A moderately murky 600-gallon pond will usually become visibly clearer within an hour or two of using this method, and continue to clear after that.
Let’s get started.
How to Clean Gross, Murky Pond Water without Chemicals
Have a look at this short video for a good overview of how this works. Please also read the instructions below to make sure you get the right materials and avoid doing anything that could damage your pond pump. And, please note that you are using these instructions at your own risk.
How to Make a Quilt Batting Pond Filter
The key ingredient is polyester quilt batting. Do not use cotton: it must be polyester. This stuff comes in flat sheets the size of a bed cover (often rolled up in a bag). It is not loose stuffing; it is all one piece. Quilt batting is traditionally used to make quilts and comforters poufy inside. But we will be using it to filter the pond water and collect up all the gunk that is making your pond green.
Here’s the quilt batting I use on Amazon.com. If you have Amazon prime, just order one bag. You can always get more if you need it later. The amount needed will depend entirely on how much gunk you have, but one sheet will be cut into piecees to provide several cleaning sessions.
For the filter container, you need a milk crate, wire waste basket, plastic basket, or anything else you can find that meets these criteria:
- larger than your pond pump
- holes in all sides to allow water flow
- acts as an open box around your pump
The purpose of this crate is to support the quilt batting while keeping it away from the pump. This will prevent stress on the pump.
After setting everything up, the crate is going to be placed underwater in your pond, either on a pond shelf or the bottom of your pond.
Place the pond pump (this has to be a submersible, recirculating pump made for home garden ponds) in the crate. You need a hose attached to the pump to direct the output water to the outside of the crate.
Next, wrap the outside of the crate in quilt batting.
In this example, I was working with smaller pieces of batting, but do use one large piece if you have it. It’s okay if there is some overlap where you fold it at the corners.
You want batting on every part of the crate where water can get through. I don’t wrap the bottom because it sits flush on the pond floor, but there’s not harm in having there too if it’s easier.
Once you submerge this in the pond, the water usually holds the batting in place. You can also add a bungee cord or some nylon rope to also secure it in place.
Be sure to position the output water hose so that the filtered water will be sent outside the crate, back into the pond.
That’s it for assembly. Now, submerge the entire thing in your pond. You can secure it in place with rocks or bricks as needed.
Before you start the pump, take some photos and videos of the murky water. Then, turn on the pump and let the filter do its work.
Keep an eye on things to make sure everything is running fine and take photos every half hour or so, or whenever you start noticing an improvement.
The quilt batting will gradually turn green/brown as it collects up the gunk from the pond water.
So long as the pump is working fine without any reduced water flow, the batting is fine. When it becomes obviously saturated in gunk and/or the flow from the output hose is weaker, it’s time to change the batting. How often this needs to happen depends entirely on your pond size, the amount of gunk, the strength of your pump, and the batting used—it could need changing a few times in the first few days or not.
As mentioned, I find a small, 600-gallon pond with moderate murkiness can show improvement within an hour or two. Often the water is clear within 4 hours. I hope it’s the same for you.
If you try this, I’d love to hear how it goes. And if you come up with a smart set up, let us know what you did. I came up with this method many years ago when we could not find a solution for my mom’s murky pond. It was pretty cool when, within a half hour of trying this, her pond finally started to clear and we could see the fish—and the bottom of the pond—again.
Pond Batting Testimonials
Over the years I have received hundreds of testimonials about this quilt batting method for clearing pond water. I’m actually yet to receive something saying it does not work for anyone who follows the instructions.
Di in Australia recently shared some photos from her pond. It’s 5×7 feet and 9 inches deep. Her pond was loaded with algae and she said it took 12 hours to clear it as shown below.
Here’s the pond BEFORE. The pictures are quite small but you can see the green water, some plants, and a hint of a fish below the mesh screen.
This next photo is a good example of what the batting looks like when it is saturdated in algae. When the water flow shows any sign of slowing down, it’s time to change the batting. Depending on your situation, this could be hours, days, or months.
While there’s still some loose algae, now you can see the bottom of the pond and all of the fish. Di joked that they probably had no idea there were other fish in there with them.
Di sent this next photo later, showing that the water continues to clear.
Once that algae is cleaned up, you can either keep using some to maintain the clear water, or switch to something like barley straw, which is also good for maintaining it.
Thanks for sharing these pictures, Di!