How to keep garden pond water clear

by Joe
Pond is in full sun . It contains about 1,000 gallons of water and is filtered by a Bio Falls filter powered by a 4000GPH submersible pump.The pond is stocked with Goldfish and has several plants. Regardless of treating the pond with several combinations of chemicals the water still looks like pea soup.
  26 answers
  • KMS Woodworks KMS Woodworks on Apr 07, 2012
    One of the common problems is the "feeds" the algae. some folk use dyes to shade the sun and reduce the algal growth.

  • Southern Trillium LLC Southern Trillium LLC on Apr 07, 2012
    Has the water been green for a while, or has it changed suddenly in the last week or so? The reason is because there is typically a spring algae bloom that occurs in ponds due to the accumulation of organic material over the winter. Then as the temp increases, the algae multiply rapidly. Even if you did nothing, the water will balance itself out in a week or two. There are other chemicals you can add that will kill off the algae and clear the water, but the best thing is to let nature do it's job and re-balance itself. There is a much more technical explanation that gets into nitrates, nitrites, etc, but the main issue is because the ecosystem is coming out of a winter state. I have had clients call before all worried about their ponds, and I tell them to wait a couple weeks and if it doesn't clear up on its on, to call me back. I have never had anyone call back after a couple weeks. The system will almost always fix itself.

  • Walter Reeves Walter Reeves on Apr 07, 2012
    I agree with Southern pond was pea soup two weeks ago and is now clear as a bell.

  • Barley Straw Bales set in the edge ofthe water

  • Laura D Laura D on Apr 07, 2012
    My pond is still green and takes longer, more like 3-4 weeks to clear up. Just the normal cycle, no chemicals needed.

  • Creative Expressions Creative Expressions on Apr 07, 2012
    An ultraviolet light helps alot in keeping the water clear.

  • Southern Trillium LLC Southern Trillium LLC on Apr 07, 2012
    A UV light is not necessary in a properly set up pond, when the ecosystem is in full operation. It is extremely common to have a spring algae bloom, and as others have already mentioned, it clears up within a few weeks. The only time we use UV lights is in formal water features or ponds that will not have any fish or plants. In these setups, there is no ecosystem to keep the water clean. Also, for anyone else wondering, a UV light will only kill water-borne algae. You can still have algae growing on the rocks, and other surfaces. The UV light can only kill what passes by it as it goes through the system.

  • KMS Woodworks KMS Woodworks on Apr 08, 2012
    When I was is grad school one of my courses was in Limnology The nutrient burst is related to what is called "spring turn over" Aside from the nitrite, nitrates ...phosphates etc. A convective top to bottom "current" mixes things up a bit . This brings the new batch of nutrients into the "photo zone" where the sun can get things going.

  • Southern Trillium LLC Southern Trillium LLC on Apr 08, 2012
    Great explanation KMS.

  • Would carp help clean it up?

  • KMS Woodworks KMS Woodworks on Apr 08, 2012
    The addition of "fish" can in some cases providing the pond is sized properly. Fish in small ponds often add more "fertilizer" to the system due to feeding and there wastes...aka fish poo is rich in Nitrogen

  • Joe Joe on Apr 09, 2012
    Thanks for the answers, but I'm still hoping for more ideas.

  • Walter Reeves Walter Reeves on Apr 10, 2012
    Did you ever say how many goldfish you have? An estimate of the total length of all the fish would be helpful. Also, how deep is the pond? And how are you maintaining the BioFalls?

  • Sherrie S Sherrie S on Apr 20, 2012
    Burco, KOI are carp. Fish both mess & clean up the pond. Plecos are the best cleanup but they can only live in subtropical/tropical climates (water must always be over 50 degrees). I have goldfish, koi and 2 plecos & have learned to ignore green algae water and brown water caused by frogs. Keep it natural. Joe, if your fish live without sickness/death then your pond is doing fine. The green & brown all goes away. Keep the filters as clean as possible. Enjoy the pond and the fish. Try to stay away from chemicals.

  • NDH Aquascapes NDH Aquascapes on Oct 20, 2012
    On thing I see you said is several plants. You may need to consider a few more plants to cover the surface also some type of beneficial bacteria helps keeps ponds clear

  • KneeDeep Ponds, Inc. KneeDeep Ponds, Inc. on Oct 20, 2012
    My first suggestion is to give your gold fish to a friend or pet store or as we do give them a new home in storm water ponds where they will fit in to the ecosystem. Reduce the number of fish when you restock the pond with Koi. They are more personable and definitely a prettier fish. They will also help manage the pond. Goggle Fish Pond Volume Calculator enter the information and you will know how many fish your pond will support. IMPORTANT: if your fish start producing spawn find someone, pet store, pond builder to share/trade for clean out services you get the idea. This is something we do with one of our customers that always has a bunch (100) when we do the spring clean out. You said you have a BioFall, do you have a skimmer? If you do, service of that can make a big difference. Come up with a schedule and stick to it as much as you can. One of the most knowledgeable guys on ponds does his every Sunday and adds Beneficial Bacteria faithfully. His water is clean and clear. His system works for him, you have to come up with what works for you. NDH Aquascapes mentioned plants...the rule, if there is one, is at least 60% of the pond surface needs to be covered. You have deep water, floating and emerging plants that come into play. These plants will benefit the pond by removing nitrates,nitrites and ammonia as it breaks down. I have at least 10 very brightly colored Koi 18-24" that I have to look for in the summer because of the plants. Oh and by the way if someone tells you water lilies won't grow in disturbed water try it anyway. I have two streams that enter my pond and lilies right in between the flow. Minimum 60%. Remember you are the creator of this mini Ecosystem but the formula for a balance in that system is the same regardless of size. I have three products that I use on my own pond and in our monthly service. Beneficial Bacteria, EcoBlast and Sludge Cleaner (bacteria). The only other additive I use in my pond is salt (99.9% pure) at the rate of 1# per 100 gal. This kills 99% of the nasties in your pond water. Last of all you need to decide what kind of pond owner you want to be. And all you have to do is look on line and you will find some one that has a pond that you would like to model yours after. I am not a 'purist' but I do build all of my ponds the same way and maintain them the same way and have been doing so for almost 20 years. Good Luck

  • Acorn Ponds & Waterfalls Acorn Ponds & Waterfalls on Oct 21, 2012
    Sounds pretty bad, but don't give up. For quick results, you could try giving the pond a good cleaning. Pump out the water, power wash, add 2-3 water lilies to the deep areas, 10 marginal plants along the edges that have 4-7" deep shelves, add 5 floating plants such as water lettuce or hyacinth, be sure to add bacteria regularly. You want the lilies and floating plants to cover about 66% of the pond surface. The plants will help take out the nutrients in the pond that algae compete for. If you have an over abundance of fish, this could be adding to poor water clarity. Any more than say 10 fish on a pond that size is too much.

  • Debra J Debra J on Feb 02, 2013
    I use a natural product by Bioverse to maintain the algae in my pond..... At first, it causes you to have to clean your filter every day, but once all the algae is gone, it runs really clear! Now if I could just keep the raccoons out of there, maybe I could put some koi back in!!!

  • Benna Commissaris Benna Commissaris on Feb 08, 2013
    The first 11/2 years, our pond was lime green It too was in full sun. We planted 3 medium River Birch trees to give it some shade. Next year water was crystal clear and has remained that way. Some shade is good for a pond, as sunlight spurs algea growth. Our pond is 9000 gallons and maintains itself now. the only thing I put in it is a bacterial boost in the spring. I don't know if adding a couple of trees is feasable in your situation, but you might try. If not, add several water lillies as Acorn Landscaping advises( cheaper too!) Your water surface needs to be somewhat protected by from the full sun. Good luck.

  • Roger Sears Roger Sears on Feb 09, 2013
    Understanding the basics of pond ecology will help understand how to keep pond water clear. Fish eat and poop in the pond. Aquatic bacteria convert this fish waste to plant fertilizer. Plants remove the fertilizer and produce oxygen for the fish. It is all connected. Many people do not add enough of the right bacteria or have enough plants available to remove all the excess nutrients. Also, being in full sun will allow the green algae to produce quickly. Floating plants such as hyacinth and lettuce will help shade the pond and remove lots of nutrients from the water. Another last resort can be the addition of a UV light. This light will kill the algae as it passes through the light system. Many people use this to help get the water cleared until the plants can catch up.

  • Southern Trillium LLC Southern Trillium LLC on Feb 10, 2013
    Roger is correct about a UV sterilizer to help with water clarity. But remember that a UV light will only kill water borne algae that is able to flow through the UV filter. You will still be able to have string algae clumps and also have algae growth on the surfaces of any rocks and liner.

  • Brian Karth Brian Karth on Feb 11, 2013
    My former employer used barley bags to keep their water pond clean. They put the bag in the filtration box and changed them once every month or if needed.

    • See 1 previous
    • Brian Karth Brian Karth on Jun 15, 2015
      @Karth Brian @we had bags that were filled with barley, they were netted bags so the barley could dispense its organic properties to prevent algae.

  • Michael Ellis Michael Ellis on Apr 16, 2013
    Roger installed a really natural looking pond with waterfall for me about 5-6 years ago. One of the most enjoyable things I have for tranquility and rest. Great place to just chill-out!

  • Julie Peasley Julie Peasley on Jul 10, 2013
    HELP! my pond stays a ickey green, I try to clean filters everyday or two, I have tried plants but they die. my fish, (gold Fish) lived all winter and looked good this spring, but then died. Can a pond be to deep? mine is about 4-5 ft. in the center. I have a bog that runs into a water fall. any ideas?

  • KMS Woodworks KMS Woodworks on Jul 11, 2013
    @Julie Peasley have you had your water tested?...with plants and fish dying you could have some pH or other issues going on.

  • Sherrie S Sherrie S on Jul 12, 2013
    @Julie Peasley how long have you had your pond? I can't imagine a pond too deep causing your problems. When I first installed my pond I bought a kit to test the water. If you are losing fish a pond test kit can tell you if it is your water. If it is not your water then there are other things you can do & I will tell you what happened to my pond and how I solved it. 1st step is test water.