Keeping pond water clear the natural way is easy, and you’ll be able to enjoy your pond again in no time. In this post I will show you exactly how to get rid of pond algae and muck, without using any harsh chemicals!
One of the biggest frustrations of having a backyard garden fish pond is not knowing what to do when the water becomes mucky, green, and gross!
Don’t worry, there is a simple way to naturally clear pond water without using toxic chemicals.
In this guide, I’ll give you all the details of how to clear pond water, and keep it clear safely, without harming your fish or plants!
Help! What’s Growing In My Small Garden Pond?
Last summer my little garden pond was overcome with a mossy, weedy growth. The pond water looked green, cloudy and disgusting.
After doing some research about small pond care, I discovered that the green stuff growing in my pond was string algae. Yuck!
Turns out that string algae growth in ponds is a super common problem.
Why You Want To Get Rid Of Pond Algae ASAP
Not only does it look terrible, but algae growth in ponds is bad because it can take over a small pond quickly. When left to grow, pond water algae can eventually starve the fish and plants of necessary oxygen and nutrients.
I was pretty nervous when I first started reading about algae in pond water.
Mainly I was worried that I’d have to use expensive chemicals for clearing my pond water. Plus, those chemicals might kill my fish and plants… or, even worse, it could cause me to have to start over from scratch with my pond.
Needless to say I was thrilled when I discovered that there is a home remedy for pond algae control.
As it turns out, clearing out garden pond algae naturally, and keeping pond water clear is easy. Whew!
How To Clear Pond Water Naturally
It sounds strange, but the answer to natural pond algae control is barley straw.
Not only is barley straw a natural pond algae killer, but it won’t harm your fish or plants – and it’s cheap to buy too.
In fact, I’ve read that barley straw is a more effective pond algae remover, and it works better to clear pond water than expensive chemicals.
Win, win, win, win!
You can find technical explanations on the internet for why barley straw naturally clears pond water.
But basically, as the barley straw decomposes it releases something similar to hydrogen peroxide (H2O2) which will eventually kill pond algae.
Whatever the technical reason is, it works great for treating pond algae!
Natural Pond Algae Treatment Use Tips
You can buy barley straw for algae control in ponds at your local garden center, or on the internet. You can also buy it in liquid form, or you can get the pellets.
When I bought mine, it came packed in small bales that were much too large for my pond (pictured above).
The package says that each bale of barley straw will treat 1000 gallons of water.
My small garden pond holds only 90 gallons of water. So I made smaller bundles out of the mesh packaging the barley straw bales came in when I bought them.
I used twine string to tie the opening in the mesh closed, and also to hang the bundle from my pond waterfall.
It’s best to put your barley straw bundle in the pond near a fountain or waterfall where the water will flow through it.
Once the straw starts to decompose, the bundle will sink so it’s no longer visible on top of the water.
Keep in mind that controlling algae in ponds using barley straw will take a little longer than it would with chemicals.
It takes a few weeks for the barley straw to begin to decompose and start clearing the pond water.
So, if you want to start seeing clear water faster, there are a few steps you can take now with these easy pond maintenance tips.
Easy Tips To Clear Pond Water Faster
Step 1: Manually remove algae from fish pond: To speed up your garden pond algae control efforts, start by manually removing as much of the algae from your pond as you can.
Don’t worry this sounds harder than it is.
An inexpensive toilet brush works great for getting rid of algae in a pond. You can remove the algae by scrubbing the sides of your pond with the brush.
Ideally, you would buy a new toilet brush to use specifically for your pond; what would be more disgusting – using an old used toilet brush in your pond, or using your pond brush in your toilet!?
Step 2: Rinse your garden pond filter daily: If you have any type of pond water filter system installed, rinsing the filter daily during this time will also help to remove pond algae faster.
If your pump didn’t come with a filter, I highly recommend you get a universal pond pump filter box. It will make keeping your pond water clear (and general pond maintenance) so much easier!
Or you can make your own DIY pond pump filter box using these super simple step-by-step instructions.
Step 3: Use hydrogen peroxide (H2O2) to help clear pond water: Another thing that works great for algae control in fish ponds is hydrogen peroxide (and no, it won’t kill your fish!).
I don’t know if there’s a special formula of H2O2 per gallon of water, so I recommend doing some research for your specific pond size.
My small pond is 90 gallons, and I added a 1/2 cup of H2O2 to the water. Pour the H2O2 over the running water of a fountain or waterfall to disperse it.
Shortly after adding the H2O2 and barley straw to my pond, and following these steps to clear my pond water faster, I started to see results.
In no time, my pond water was crystal clear, and it stayed that way all summer.
How To Keep Pond Water Clear Naturally
Now I put a new barley straw bundle in both of my little garden fish ponds in the spring as part of my regular small pond maintenance schedule.
Since doing this, I’ve been able to avoid algae growth in my ponds, and keep the water clear. One small barley straw bundle lasts all summer.
Another thing I make sure to do as part of my regular fish pond maintenance tasks is to remove the leaves and other debris from my pond.
My pond skimmer net makes this task super easy! Regular pond maintenance is very important to ensure the water stays clear! Learn how to properly clean your pond here.
If you’re having problems keeping your pond clear, and algae growth is not the issue (or if you’re not sure what the problem is), then I recommend testing the water.
You can get an inexpensive pond water test kit that is specifically made for testing pond water, and that will help you figure out exactly what type of treatment the water needs.
I love my garden ponds again now that I the water is clean. It’s nice to be able to watch my fish swimming around in the crystal clear pond water, feeding on worms and other bugs that fall into the pond.
Plus my ponds are constantly filled with frogs and salamanders too – a wonderful sign of a healthy pond!
Related Post: How To Winterize A Garden Pond Step-By-Step
Keeping pond water clear and algae-free isn’t that difficult when you know how. Once you have it cleared out, it will be much easier to maintain it too – and you’ll love your garden pond again!
Recommended Reading
- Backyard Water Gardens
- The Water Gardener’s Bible
- Water Garden Idea Book
- Encyclopedia of Water Garden Plants
More Gardening Techniques
- Growing Vertically: The Ultimate Vertical Garden Guide
- Plant Propagation: A Detailed Guide For Beginners
- How To Build A Rain Garden Step-By-Step
Share your tips for keeping pond water clear naturally, and backyard pond algae control in the comments below.
Patt says
I use Barley straw as well. I do like it. I use it in 3 ponds. But I put one in, in the spring, then another one in the middle of the summer. But I do recomment it. I make sacks for the straw and put the straw in it.
Amy Andrychowicz says
Awesome, thanks for sharing your experience with using barley straw to get rid of pond algae. Glad to hear it works well for you too! 🙂
Diane says
My new pond was starting to get murky. I used the barley straw; in just 2 days the water was clear right to the bottom. I don’t know why some ponds don’t respond well to the barley but mine was a few day clear method.
The bale has just now absorbed enough water to sink and I’ll watch to see if there are any changes.
I have a 500 gallon tank, 4 ft deep, built above ground, 3-tiered fountain, nine Koi and 30 algae eating snails.
My Koi are happy and fun to watch as they “frolic” throughout the pond. I have many “hide-y” holes for them to swim around and through.
I’m most pleased with the pond and it requires little work other than cleaning the pump every couple of weeks.
I am going to use a tank water heater regulated just to keep the water from freezing and possibly keep my waterfall in use year round.
I hear that many people remove the pumps for the winter.
Amy Andrychowicz says
Awesome, so happy to hear that barley straw worked so fast to clear your pond! Woohoo! It gets very cold here in MN, so I have to use a pond heater to keep mine from freezing over, and I must turn off the waterfall. I don’t remove my pump though, since the heater keeps my pond from freezing to the bottom. Here’s a post I wrote all about how to winterize a pond.
Brenda says
Hi, I have a very large pond with a 4 Ft waterfall. I don’t remove my pump in the winter and I don’t have a heater either, I just run two bubblers in the pond it’s self, so my fish have two air holes for oxygen and pond gases to escape. I have only had it for one winter and all but’s two fish did well, but they were from a pet store. I shut the waterfall off in the winter and only run the bubblers in the lower pond.
Joanne Lebo says
My husband and I have a quarter acre pond with a stream running through it. We tried to keep it clean manually, but we couldn’t keep up with it because of separate health issues. Our pond has about 100 koi and several types of frogs that live in it. I am sure there are other sweet critters as well. Our issue is that the pond has a lot of overgrowth and it smells so horrible I could almost gag. Where would I get a free test kit to see what problem needs addressed exactly? I have ordered a few hundred dollars worth of different pond cleaning stuff and it will be delivered this weekend. We just don’t know which way to turn at this point. All the things I’ve ordered claim to be safe for pond life.
Amy Andrychowicz says
Oh bummer, so sorry to hear you’ve been struggling with stinky and mucky pond water! I’m not sure where you could a free test kit, but they’re not very expensive to buy. Here’s the one I have… pond test kit.
June says
You need oxygen in your water. We had the problem of stinky water. Added a windmill, attached to it was a hose and a air pump. Put a weight on the hose with the air pump and sunk it in the deepest part of the pond. The windmill catches the wind and turns the blades on the fan, that pumps air down through the hose in the bottom of the pond and releases oxygen. You see the air bubbles on the top of the water. We also added a floating electric fountain. This aerates the surface water. Purchased pond muck cleaner. It also helps if you can get rain water to flow into the pond. We have a 4 foot ditch that surrounds the pond and put a pipe that connects the ditch to the pond. When it rains heavily the ditch water flows into the pond. All of this has helped tremendously. No more stinky pond. We have stocked it and it is beautiful.
Arch.Tung says
More than likely the smell is from the sulfur created by anaerobic bacteria. You have a big pond and probably many dead vegetation blocking the flow of your pond thus reducing the oxygen. Anaerobic bacteria helps reduce the nitrate level in your pond taking place of your dead plants. I use to create an anaerobic filtration system for my reef tank to keep the nitrate level low. They require low oxygen level to thrive and remove nitrates and cause the smell due to stagnated water. Clean all dead and decayed debris and add a large pump to aerate the pond.
Art D says
Another tip for filtration, apparently activated charcoal is this:
Make a fire using Hardwoods. Once all of the wood have become Red Hot Cherry Coal feed your fire water, as much as it takes to subdue the coal.
Now the charcoal has become activated. Break into whatever size pieces you need and thoroughly rinse.
Note, it will smell like a campfire when rinsing but that will quickly pass. I’ve done this myself and find it’s a lot cheaper than buying already activated charcoal at the store. I haven’t yet tested it for drinking water, but that’s on the do.
Amy Andrychowicz says
Great, thanks for sharing your method of clearing pond water! I like the charcoal idea.
Arch.Tung says
In addition, you can reactivate the charcoal with heat and reuse it again many times. Charcoal have large surface areas to absorb surfur, phosporus and nitrates thus clears the water. By heating it up around 400 degrees F for about 30-60 minutes essentially cooking the bad stuff out you can rinse and reuse. Sams warehouse have charcoal wood for grilling that you can buy but i would definitely heat in oven first just to make sure all bad chemicals that were used to process the charcoal are gone to keep the fish safe.
Bill says
I have two ponds, the one in the sun is a constant cloudy algae problem, but the one in the shade is always clear as drinking water, without any additives, filtration etc. Pick the location in the shade to rid yourself of all those problems, or shade it or move it if possible.
Amy Andrychowicz says
Great tip for people looking for the best location to build a new pond. Though I agree that a pond in the sun will likely have more problems with algae growth, moving it to the shade won’t necessarily solve that issue. My pond in the front is in full shade, and I still have to fight algae in there.
Melissa Johnson says
I know this is off the subject, but I am planning a pond for my ducks and this is all wonderful advice. Does anyone know if i can put koi fish in the pond with my ducks?
Amy Andrychowicz says
Sure, I don’t see any problem with putting koi in a duck pond.
marylu says
Ducks will eat or kill small koi (fish 4-5 inches in length would be in danger).
Amy Andrychowicz says
Really?? I have ducks in my pond every spring, and they’ve never eaten any of my fish.
James Parson says
I live in southeast Texas and have a 5 acre lake, and I desperately need someone to help. It’s overtaken by underwater growth and I don’t know what to do. If you know of someone in my area that could come & take a look I would be most grateful.
Amy Andrychowicz says
Sorry but I don’t know much about lakes. I would call your local city or state department of agriculture and talk to them about your options. Here in MN the lakes are owned by the state, so that’s where I would start.
D says
Try contacting Texas A&M. They might be able to send someone out, or get you a test kit of some kind.
Robin says
Our pond holds 3600,00 gals of water, how much pine straw would I need for this? I have. 75 large goldfish and Koi, and about that many babies. Yes they seem happy. Lol
Amy Andrychowicz says
The barley straw that I buy says that each bale treats 1000 gallons. You may be able to find larger bales for a larger pond like yours.
Shirley McKinney says
My pond holds approx. 1200 gallons of water. I do not have the green stuff yet this year but the water is dirty looking. What to do?
Amy Andrychowicz says
Here’s a detailed post about how to clean a fish pond that will give you all the info you need.
Dale Burleson says
I live in Thailand and do not have access to Barley straw. I used rice straw and it worked just as good.
Step 1.
Soak a bundle of rice straw for 3 days in water. Drain after 3 days.
Step 2.
Wrap rice straw in netting.
Step 3.
Place straw in flowing water and leave it.
Should start seeing results in about 2 to 4 weeks.
After 3 weeks the alge in my pond started to disappear and pond water is now clear and alge is nearly gone.
Amy Andrychowicz says
Great, thanks for sharing your tips and experience for using rice straw instead of barley straw to clear your pond water!
Keith Tuck says
Another good way of keeping algae down is to have an Ultra Violet lamp in your filter system. I used to have a filter box with built in ultra violet lamp when I had a small pond and the water stayed crystal clear.
Amy Andrychowicz says
Wow, cool. I’ve never heard of a pond filter with an ultra violet lamp. Thanks for the added tip.
Sharin says
Can u put devil vine n ur garden pond? Or will it take to much oxygen out of my water. Don’t want to kill my goldfish or koso fish
Amy Andrychowicz says
Plants actually help to add oxygen to the water, they don’t take oxygen out of the water. I’ve never grown devil vine (I think you’re talking about pothos?) in my pond before, but I don’t see why you couldn’t give it a try. I have water lilies in mine, and overwinter them in there with the fish.
Art D says
Amy, not certain about aquatic plants but I do believe that the root system for plants on land breathe oxygen and exhale carbon dioxide just as we do. it’s just that the top side of the plant does the reverse at a greater rate usually, so overall the plant generates more oxygen than it consumes. If researching this proves that I’m wrong, preemptive apology here. 🙂
Kristy says
Our goldfish got sucked into the filter/ pump area. Any suggests for this?
Amy Andrychowicz says
Oh no! So sorry to hear about your fish! I’m not sure what type of filter or pump you’re using, but I’ve never had that happen to my fish. I would recommend getting a universal filter box if that would work with your pump. That’s what I use, and my fish have never been sucked up.
Cindy says
We use panty hose. WTer filters through but fish and frogs do not. Pool and big name hardware stores with garden centers sell them specifically for the pump and filter. They allow the water to flow through trapping debris and thicker algae.
Gay says
Do you have a problem with raccoons or water snakes invading your pond?
Amy Andrychowicz says
I haven’t had any problems with critters invading my pond. We do have lots of frogs and I’ve also seen salamanders in the pond, but nothing invading it (well, unless you call 15 frogs having a party in there on a hot day an invasion, LOL!). I’m sure that wildlife like raccoons drink from my pond regularly (I’ve seen lots of birds and even squirrels taking a drink), but the raccoons have never done any damage or eaten my fish (that I know of anyway). Knock on wood!
Paulette says
Hi I read that you have frogs in your pond. My pond is also about 90 gallons so my goldfish are relatively small maybe 4”. I’ve always loved the idea of having frogs but afraid they would eat the small fish. How big are your fish? Do you have a problem with frogs eating them? Thanks
Amy Andrychowicz says
I also just have goldfish in my pond, and have never had problems with frogs eating them. Since my pond is outside, I would never be able to keep the frogs out anyway, LOL!
Theodore c Young says
Barley straw only kills the string algae. In order to deter the other types of algae make sure 50% of your pond is covered with plants. Too much sun promotes the growth.
Just sayin
Amy Andrychowicz says
Using pond plants to shade the water from the sun is a great idea, thanks for the tip!