Pond Help

Need help with your pond? Use the drop down menu below to see if we’ve already answered your question. Or visit our Pond Blog for helpful tips and advice from leading pond experts.


Man-made chemicals & UV sterilizers create a dependency that actually weakens your pond biology & prevents natural water chemistry from balancing. Consistent use of Nualgi Ponds products can decrease or eliminate the use of harmful pond chemicals.

Natural pond care is better!

It’s not because it’s better for the fish & plants.

It’s not because it’s safer for your pets and kids (or grandkids). And it’s not even because it’s cheaper.

It’s because going natural is the easiest way to care for your pond over the long-term. You simply have to do less work. You get the beautiful tranquil pond you dreamed about, just without the endless pond maintenance.

Not sure where to start? Visit the Nualgi Natural Pond Cleaner page for more information.


If you close your pond down correctly in the fall/winter, you should have a much easier time controlling nuisance algae like string algae and removing muck in the spring. If you find yourself with an excess amount of sludge, slime, and stinky materials keep this guide in mind when wrapping up your pond at the end of the season.

Opening Your Pond for Spring – 6 Pro Tips to Remember!

Throughout the process, remember to be gentle, especially if you have fish because their immune systems are still low from the winter months. Everything will increase gradually including fish activity, water temperatures, and the amount you are feeding.

1. Clean Out Debris From Your Pond

This is very important.

Cleaning up is sometimes messy, and if not done properly at the end of last season, you could be dealing with a toxic mess (figure of speech: unless you have blue green algae in your pond).

When cleaning, make sure you vacuum the bottom, take care of leaves, pull out the decaying plants, and give your pots a scrub. While cleaning out the pots this is a great time to add water lily and plant fertilizing tabs to stimulate their growth. If you notice extra muck in your pond, think about adding some Nualgi Muck Remover tablets to naturally eliminate pond muck and sludge and keep your pond clean.

Using pond plants for algae control is a great natural approach, but too many plants and debris can lead to extra nuisance algae.


2. Begin Water Filtration and Re-Install Pump or Skimmer

When starting to cycle your pond you will want to check if pond aerators are 100% open and functioning. Check that all the mechanics are working with proper flow and if you have a waterfall, double check that nothing is stuck in the impeller. Keep in mind that air stones can remain off until water temperatures reach 73 + degrees.

If you live in an area where your pond can dip below 40 degrees during winter, be sure to only activate your pump or skimmer once your water reaches back over the 50 degree mark. For warmer climates, you may have been running pumps and skimmers all winter. If so, continue use of these tools as necessary.


3.  Supplement Nitrifying Bacteria to Improve Your Biological Filter

Get that biofilter churning by adding nitrifying bacteria to your pond. 65 degrees is the optimal temperature for the bacteria to help your bio filter come back to life, don’t add in algaecides as they can add more toxins that are dangerous to your inhabitants. Remember, Mother Nature needs time to balance your water and patience is your friend!

Use Nualgi Beneficial Bacteria as an additive for your pond at this point to keep your water crystal clear! It is important to recognize the power of maintaining a natural biological filter as part of your Spring pond opening.


4. Evaluate Koi Fish Health

Overfeeding and feeding too early in the season are two of the most common and costly mistakes made by hobbyists!

The health of your fish contributes to the overall health of your pond. Make sure your fish are clear of any ulcers or white/cloudy eyes/patches of skin. Don’t stress if they seem unhealthy, adding medication to your pond this early will not be the quick fix you’re expecting.

When evaluating your fish do not net and put in a bowl. Their immune systems are still low until they’ve eaten for three weeks or the water hits 68 degrees. While cleaning/evaluating try not to  jar the fish, they won’t move around much at first and are delicate.

Pro tip: Feed with medicated food, antibiotic floating food will be better than sinking food. Contact Cali Koi – Los Angeles Koi Specialist for a unique recipe.

Remember to let the pond cycle naturally rather than adding a lot of chemicals. If it’s later in the season and you are still having sludge, add in digesting bacteria. Fish will be picking around and could eat your other bacteria, so wait until later.


5. Test Your Parameters Consistently

  • Temperature: 65 degrees Fahrenheit is the ideal temperature for your biological filter to flourish. Generally, keep your pond in the 64-73 degrees Fahrenheit range as consistently as possible. Waterfalls, aerators, and additional shading will help keep your pond cool heading into Spring and Summer.
  • pH: Keep your pH as close to the ideal 7.3-7.7 range as possible, depending on what type of fish you’re keeping in your pond. Monitoring your pH levels will tell you when to feed (adds ammonia), add nitrates (decreases ammonia), or add salt (decreases nitrates). For more information on how ammonia affects your pond visit this informational guide from the Southern Regional Aquaculture Center.
  • kH: Aim to keep your kH (Carbonate Hardness) levels as high as possible. Having high kH levels will significantly increase the effectiveness of your filter, and is a very necessary quality of your pond during this initial cycling period. We recommend using air stones, which drive off CO2 and increase your water hardiness.

In general, if any of these levels are not working out to your satisfaction, it may be worth your time to try a 25% water change to cycle out the water. Be sure that the water you are adding is of equal or very similar temperature to the water currently in your pond. If the water is coming from your home faucet, remember to dechlorinate before adding.


6. Add Floating Plants and Enjoy Your Pond

Wait until 69 degrees to add in your tropical plants. At this point your pots will now be flourishing from the pellets you added and the water will now be completing its cycle. The lilies will come back on their own and now it is your time to get a drink while watching those Koi circle the pond.

As with any hobby it is important to remember why you are involved in the first place. Doing maintenance on your pond is directly tied to a zen lifestyle that is reinforced by ancient cultures in Japan.

If you do not smile while working in your beautiful backyard sanctuary, then it’s about time to hire a pond maintenance company or teach your children to clean the water this time of year. If only dogs had opposable thumbs…

With the help of Nualgi Ponds to keep your water clear you can spend more time enjoying your sanctuary and less time maintaining it. This breakthrough nanotechnology product not only keeps your water clear but it even naturally produces extra food for your fish!

For more information on Spring opening, visit our blog post here.


It’s that time of year again! Fall is here, and with it comes colorful leaves, sweaters and the start of the holiday season. But fall also brings a whole host of challenges for your pond, its plants and the aquatic animals that call it home. With a little planning and preparation, you can make sure your pond—and its flora and fauna—makes it through winter safe and sound.

To Winterize Your Pond or Shut it Down?

During the summer months, you can usually sit back and enjoy your pond with minimal maintenance. With the fall season comes cooler temperatures and shorter days—and that means you need to start thinking about your pond’s aesthetics, water chemistry and fish health.


Your pond is a work of art, but it’s also an ecosystem that needs to be maintained in order for it to thrive through the winter months. Essentially, you have two options in the winter: take the proper steps to protect the pond or shut it down for the winter. Which option is best for you depends on a few factors. First and foremost, you must identify your specific climate type.

Click here to identify your climate type (warm-to-moderate or moderate-to-extreme-cold) and for the steps you’ll want to follow for winterizing in each climate.

Dog swimming in pond with Blue-green algae bloom


Green pond water can be caused by two phenomena – New Pond Syndrome (NPS) or a result of nitrate, nitrite and phosphate levels being too high. 

It’s important not to confuse new pond syndrome with only green pond water, which in many cases is a healthy part of the natural water cycling process. A key differentiation between these two phenomena is the effect on the fish – monitoring your fish health and water quality will prevent any misdiagnosis of NPS. 


If your pond is turning dark green, there is foam, and dark green/black slimy algae buildup on sidewalls, then you may be on the way to New Pond Syndrome. Click here to read more on New Pond Syndrome, its effect on your fish and how to fix it. 

If your nitrate, nitrite and phosphate levels are too high you may not have enough beneficial bacteria in your pond. Click here to learn about Nualgi Beneficial Bacteria or contact us through our troubleshooting form for more assistance.

I have a problem with string algae

String algae is a filamentous species that attaches to plants, hangs from rocks in waterfalls, or hangs on the surface of the water (which is referred to as Blanket Algae). The long strands tangle together and form thick mats that can double their weight within 24 hours!

Though it may appear ugly, string algae is not a major danger to your fish’s health but it can be to the overall appearance/water clarity of your pond.

To stop string algae: You must reduce the nutrients that fuel the algae growth cycle. Learn how Nualgi Ponds users combat algae in their backyard ponds. 

Step 1. Physically Remove String Algae

This is your best method for removing string algae. Though it may seem dirty, it is essential to do before treating so you can reduce the amount of decay. Pull the biggest bits near the base, pull hard, and put it into a bucket. It can sometimes be difficult to pull out a lot at one time since it is soft and malleable.Physical removal is the fastest way to get algae out of your pond and take the next step to crystal clear pond water. Winding around fingers/hands is the best approach aside from a toilet or long lint brush to roll it up with. The hand approach is easier because the thin strands are difficult to clean away from brush bristles. Wearing gloves is not required but may keep you cleaner. Use a long handled brush to pull out the algae at depth.


Step 2. Treat Water and Kill Off Remaining Algae

Some sources suggest using a pond algaecide to kill off the remaining algae but we never recommend unnatural chemicals even if the labels state they are safe for fish and plants. We stick to natural solutions for algae control and recommend a combination of Nualgi Natural Pond Cleaner + Nualgi Beneficial Bacteria to speed up the process. [CHECK LINK IS STILL GOOD ON WEBSITE]

Normal green hair-like or carpet/blanket algae which grows on pond walls and some rocks is best left untouched and completely acceptable. However, it is possible that Nualgi will eventually eliminate this type of algae. We like to think of our process as out-competing and starving the algae rather than killing it.


Step 3. Add Extra Plants and Remove Decay

Place quick growing and reproducing plants in your pond to increase oxygen content. Make sure you take out the decaying plants first, as they will not help your fight against algae. Choose plants that will grow larger, consume a lot of nutrients, and will not require a lot of upkeep.

We recommend Water Lettuce, Irises, and Cattails for the spring and summer. Marsh Marigold is one of the earliest plants to sprout in the season and helps to prepare your pond for the spring. A great winter plant is Water Hawthorne which does best in cold months and has the best prices during the summer.

You can solve many problems as a pond owner by placing plants to out-compete algae and suspend algae for excess nutrients. Just be careful to not add in any plants that already have algae attached!


Step 4. Find the Cause of the Algae Growth

Look for potential causes of string algae by testing your water quality. If algae is growing at a problematic level then it is time to look beyond the algae and mat and deeper into the pond chemistry. High pH and Phosphorus levels are the leading cause of algae blooms.

Examples of what can cause high pH are the clearing of algae blooms, excessive plant growth, overstocking of fish, and the introduction of foreign materials (untreated concrete, rocks containing limestone or calcium/granite). The most common cause of high phosphorus is from fertilizers that have leaked into the pond water. Iron is also a major contributor as well as grass clippings that find their way into the pond after mowing the lawn. Scoop green grass blades out immediately.

Step 5. Feed Koi & Fish Less to Reduce Excess Nutrients

One of the most common errors by fish pond owners is to overfeed their fish, thus adding excess nutrients to the water. If there is any food left in the pond uneaten, you’ve fed your fish too much. By feeding less you also increase the fishes’ appetite for other substances in the pond. Like algae! Try feeding your fish less this summer and see how fast they will cut through a string algae mess.

A few corbicula clams in the pond is an excellent way to keep excess nutrients cleaned up and in check. Each clam filters up to a liter and a half of water per hour. Read other Koi Pond Care Tips for the Summer.

Click here to learn more about the role of algaecides, UV filters and barley straw in controlling pond algae.

green algae in pond

What are the warning signs for blue-green algae?

Did you know that blue-green algae isn’t even technically algae at all? The term refers to cyanobacteria; where cyan refers to the blue-green color. While similar in appearance to algae, cyanobacteria or blue-green algae is actually a bacteria that has potential to cause harm to your aquatic ecosystem and its surroundings (including you and your pets).   

Warning signs for blue-green algae are dead fish, unexplained sickness/death of a domestic pet (that may drink from/be in contact with your pond), unpleasantly scented water and skin rashes following contact with the pond water. 

Click here for more information on blue-green algae, including how to prevent it and how to protect your fish, pets and pond ecosystem.

How do I build a natural pond?

Building a pond is a big undertaking, a lot of planning, time, and resources are necessary to make this work. But the rewards for building a natural pond are amazing and can provide years of enjoyment. 

Some questions to ask yourself before you get started on this new adventure are:


  • What is the purpose of my pond? Is it for critters, plants, or both?
  • Are there any obstacles to construction?
  • Where is the water draining when it rains?
  • What strength of filter will I need?
  • Do I want an under-gravel filter?
  • Where is my filter going to be located?
  • What depth do I want to build my pond? 


We spoke with avid pond hobbyist Judd Bristow to help you address these question and provide you with detailed steps on how to build a pond the natural way! Click here to read on.

How do I choose the right pond liner?

Choosing the right liner for your pond can appear complicated, but it doesn’t have to be. A good liner will not only contain water in your pond, but it will also help to keep sediment and other debris out to make it easier to maintain. When choosing your pond liner, take into consideration your expected inhabitants for the lifetime of your pond, you might not always just want goldfish and a few ferns. Koi fish have different demands than a simple backyard water garden and the more affordable choices could lead to large algae overgrowth in the future. 

Click here to read the full article on pond liners, including sizing, thickness & materials best for all your pond needs!

Is a UV pond filter the best choice for my pond?

Wondering if you need a UV filter? Or confused about how they work? Don’t worry, we’ve got your answers here. 

Did you know that “UV pond filters” are actually UV sterilizers, and that they use UV light to kill ALL algae and microorganisms in your water, both good and bad? Ultraviolet Germicidal Irradiation (UVGI) uses short-wavelength UV light to kill or inactivate organisms. The light destroys nucleic acids, disrupts DNA and leaves cells unable to perform essential functions. This process “sterilizes” the pond water. 

UV filters are expensive to run with recurring monthly costs and require an additional filter to remove the debris produced by the UV light.

If you maintain a balanced ecosystem in your pond you eliminate the need for algae-killing UV systems. This includes good filtration and water circulation, regular water changes, and inclusion of plants and fish for oxygen production. 

Click here to read more about UV filters, including pros and cons as well as natural alternatives to obtaining crystal clear water and a healthy, balanced pond.

How do I choose and maintain my pond plants?

By acting as a natural filter, pond plants act to balance your water and maintain a healthier pond environment. They also provide natural competition to nuisance algae and decrease maintenance needs. 

In our blog post on pond plants, we address questions like:

  • The role of plants as natural pond filters
  • How aquatic pond plants combat algae growth
  • Benefits of water plants for fish and wildlife
  • Types of aquatic plants for your water garden
  • Climate and location affect on plants
  • Choosing the right water plants for your pond


Read on for answers to these questions and more!

How do I take care of fish and other pond inhabitants?

Your pond is a delicate ecosystem – and that applies to your pond inhabitants too! Temperature changes, thunderstorms, overstocking, breeding and chemicals outside of your control are only some of the factors that can affect the wellbeing of your favorite pond inhabitants. 

It is important to know that most parasites and bacteria that can cause disease in fish are present in your pond all the time, but generally there is a healthy balance in the ecosystem that keeps the fish healthy. Once the balance is disturbed, such as when fish health is compromised by increased stress, the disease organisms can overwhelm the fish and an outbreak of disease can occur.

Recognizing stress symptoms in your fish is important. And keep in mind that symptoms may not always appear right away – it can take up to 14-21 days after a stressful event for symptoms to show up. 

If you’re looking to understand what’s going on with your fish, click here to read our full blog post. 

If you’re like us and want to incorporate fish into your pond ecosystem not only for their beauty, but also for their hunger for algae click here for recommended algae-eating fish types based on pond size/type, water conditions & other inhabitants. 

And if you’re already lucky enough to be a proud Koi owner and are looking for tips to bond more with these majestic creatures, click here for our top tips on hand feeding and bonding with your Koi. Not only can you benefit from forming a relationship with these smart fish, but if you familiarize yourself with your own Koi fish’s personality, you can be aware of anything out of the ordinary in water quality or predators.

Our Pond Blog and Pond Help pages are full of helpful resources to make managing your pond easier.

If you’re still struggling, don’t hesitate to reach out to our team of Pond Experts.

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