Swim Pond - string algae after spring run off


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First year (2018) - late summer warm water (filled with city water) little to no string algae (could be easily controlled with manual removal)

Aug 2018.jpg


I have attached some pictures of the pond below. We built our pond summer 2018 iand we didn’t have any algae problems the first year even in the warm weather. The pond was filled with approx 70,000L of city water.

In the fall of 2018 and then in the subsequent spring we had a substantial leaf drop and soil runoff into the pond. I believe this is the major factor that has resulted in large algae issues since then, though we continue to have excellent water clarity. We have adjusted the drainage and removed the tree responsible for the leaf drop so we do not have these issues going forward. t

Since summer 2019 we had a large string algae problem. We didn’t think about changing out the water until this year. A couple weeks ago we changed out 50% of the water in the pond. Just draining the pond and vacuuming the biomass out of the bottom and route and changing the water killed the algae back for a week or two but it is back with a vengeance. We’ve never had any issues with water clarity or pea soup algae only The string algae at the bottom and around the plants.

We’re trying to get some lilies established but we didn’t realize for the first two years that they need to be potted and won’t grow alone in the gravel. We are considering retrofitting a skimmer and a water feature to filter the water additionally.

Design: The water is circulated under gravel by four bubble pumps pulling water through pipes under the bog area and aerating the water. There is no additional filtration system.

My question: since the issue seems to have been caused by nutrient run off and leaf drop will a 100% water change out solve the issues (we had no algae in the first year)?

Water quality - unknown (do not have a kit)

* Ammonia Level (pond)
* Nitrite Level (pond)
* Ammonia Level (tap water)
* Nitrite Level (tap water)
* Ph Level, pond (If possible, KH, GH and chlorine)
* Ph Level, tap water (If possible, KH, GH and chlorine)
* Brand of test-kit used and whether strips or drops?

Other useful information:
* Water temperature? - very warm in shallow zone (12" deep) usually a couple degrees below day time high
* Pond size and how long has it been running? 45'x35' with 12'x24' 6.5' deep zone; approx 70,000L
* What is the name and size of the filter(s)? bog only
* How often do you change the water and how much? did one 50% water change this spring
* How many days ago was the last water change and how much did you change? 1 month; 50%
* How many fish in the pond and their type? no fish; lots of frogs, bugs etc. wildlife also visit occasionally
* What kind of water additives or conditioners have you used? hydrogen peroxide (1L @ 3%/1,000- L)
* What do you feed your fish and how often? n/a
* Any new fish added to the pond recently? n/a
* Any medications added to the pond? n/a
* List entire medication/treatment history for fish and pond n/a
* Any unusual findings on the fish? n/a
* Any unusual behaviour like staying at the bottom, not eating, etc.? n/a

First spring (2019). Many plants did not survive the winter freeze. Also we did not understand the importance of potting/fertilizing plants. We had significant leaf drop in fall 2018 and spring run off from ground into pond in spring 2019. The tree has now been removed and drainage improved so we did not have these issues in spring 2020. I vacuumed out the leaves and silt (run off) in spring 2019.

June 2019.jpg


Late summer 2019. Warm water at this point was contributing to massive string algae. We tried to increase our plants (harvested from local water ways). We still were not potting/fertilizing. It was a losing battle...

July 2019_2.JPG

Algae was choking out everything.
Aug 2019 Algae1.JPG
Aug 2019 Algae3.JPG

and clinging to the walls
Aug 2019 Algae2.JPG

some visitors in fall 2019 (you can see heavy string algae even with the cooler water)
Sept 2019 Deer +Algae.JPG

Spring 2020 crystal clear and COLD water before plants came up
April 2020.jpg

String algae was back with a vengance once the water started to warm up in may. We have added many additional plants and many potted lillies since the photo was taken.
May 2020 Algae.jpg
 

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addy1

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Welcome to our forum, that is a neat set up!
 

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How beautiful a swim pond. My guess is one of the issues is due to phosphates they use in city water. Basically the same as fertilizer run off which causes algae blooms in our bays in the US. Unfortunately it’s very hard to remove and changing the water with city water isn’t going to help.
 
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Welcome to our forum, that is a neat set up!
Thanks :). I'm hoping to get some water tests in the next couple days to get a break down of what the possible nutrient situation is. Do you think that replacing the water to 'reset' as in first year could solve the issue? Given there was basically no algae in year 1 I think the runoff and leaf drop in first year is the main culprit. Though reading up on things the concrete may be leaching into the water effecting ph etc.
 
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How beautiful a swim pond. My guess is one of the issues is due to phosphates they use in city water. Basically the same as fertilizer run off which causes algae blooms in our bays in the US. Unfortunately it’s very hard to remove and changing the water with city water isn’t going to help.
Thanks. We were inspired by David Pagan Butler. I'm going to get some test kits to see what is going on with water. We did not have this issue in first year (using city water) before leaf drop and surface run off... :s
 
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What is the best test kit to get? strip vs test tube? which tests are necessary if not keeping fish?
 
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That's a neat setup and once all the plants fill in will be a sight! Any kid wold love poking around there.

I think the lack of algae issues that first year is just due to the natural time it takes for life to form in a large body of fresh tap water. Changing out the water now won't do much for any string or algae growing on any surfaces. As noted, the tap water will have some phosphates which is food to the algae anyway, and would quickly return to it's current state.

If you image a natural pond of this size out in full sun... it would be full of algae on all surfaces, probably the color of pea soup, and lined with plants and life all around. So to fight off the 100% natural look, I would think you need to increase your filtration regimen so that food that the algae is consuming now is instead consumed by the plants and bio load in the gravel first.

Others will have to jump in on ramping up the bog filtration system beyond just the four bubblers pulling water down through the gravel.
 
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The liquid testkits are The best. Api liquid pond kits are what most recommend. In order to fight the algae, you need lots of plants. Look for plants that like wet roots, iris is one that I know does. And the faster they grow, the faster they will starve the algae. If your pond freezes, set up a way to remove a large chunk of the plants each fall, and plant them in the ground or in planters for winter. Making plant holders of window screen would make that easy.
 
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Update with test API drops kit:


* Ammonia Level (pond) - between 0-.25ppm
* Nitrite Level (pond) - 0ppm
* Ammonia Level (tap water) - 0 ppm
* Nitrite Level (tap water) - 0 ppm
* Ph Level, pond (If possible, KH, GH and chlorine) pH 8.2 (high - due to peroxide application?), KH-60 GH-30
* Ph Level, tap water (If possible, KH, GH and chlorine) pH 7, KH 0, GH 0

Waiting on delivery of the phosphate test kit... that may be the culprit.
 
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When the plants take off the string algae will be a thing of the past.
This is my bog area with the string algae just after winter thaw. My bog isn’t even a year old yet. Plants are not well established.
 

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String algae is a weird thing... lots of posts this year on this site and others about how bad the string algae this season so far compared to prior years. In the midwest, I want to attribute it to the very mild winter we had since that's the only difference from prior years. Typically I doesn't last long before it just stops growing and isnt' an issue, but this year it was for over a month of dealing with it. Don't know what to think for people in the warmer parts of the country.
 

addy1

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It doesn't have a chance in my ponds, to many plants sucking out the nutrients. I get the smallest amount that just goes away, a bit on the hornwort early spring.
String algae is a weird thing
 
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Looks like 0.25 mg/L phosphate in the pond and about 1mg/L in the city water. I guess a water change out is not going to help lower phosphate content...
 
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The algae is up taking some of the phosphates as nutrients. If you look at many managed ponds they use a method to skim the surface which would be an easier way to remove the string algae. Normal pond Skimmers I don’t think would work for you though, too small and need to clean too often. Near where I live there are run-off ponds along interstate on and off ramps. They use huge collectors in the center to skim but I’m not really clear on how the system works as a whole.
 
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I read somewhere that geotextile on top of the drainage pipe under the gravel can clog and cause a lack of flow through the bog. I noticed that the only area of our pond that does not have geotextile over the agg pipe is clear of algae vs. the other areas where the geotextile over the agg pipe appears completely clogged with fine silt. Do I need to dig up the agg pipe and remove the geotextile that is blocking the flow?
 

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I read somewhere that geotextile on top of the drainage pipe under the gravel can clog and cause a lack of flow through the bog. I noticed that the only area of our pond that does not have geotextile over the agg pipe is clear of algae vs. the other areas where the geotextile over the agg pipe appears completely clogged with fine silt. Do I need to dig up the agg pipe and remove the geotextile that is blocking the flow?

Without a doubt, geotextile fabric will clog. That is what it is designed to do....catch sediment. If it is inhibiting the flow of water through the bog then yes I would remove it.
 
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TheFishGuy

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First year (2018) - late summer warm water (filled with city water) little to no string algae (could be easily controlled with manual removal)

View attachment 129639

I have attached some pictures of the pond below. We built our pond summer 2018 iand we didn’t have any algae problems the first year even in the warm weather. The pond was filled with approx 70,000L of city water.

In the fall of 2018 and then in the subsequent spring we had a substantial leaf drop and soil runoff into the pond. I believe this is the major factor that has resulted in large algae issues since then, though we continue to have excellent water clarity. We have adjusted the drainage and removed the tree responsible for the leaf drop so we do not have these issues going forward. t

Since summer 2019 we had a large string algae problem. We didn’t think about changing out the water until this year. A couple weeks ago we changed out 50% of the water in the pond. Just draining the pond and vacuuming the biomass out of the bottom and route and changing the water killed the algae back for a week or two but it is back with a vengeance. We’ve never had any issues with water clarity or pea soup algae only The string algae at the bottom and around the plants.

We’re trying to get some lilies established but we didn’t realize for the first two years that they need to be potted and won’t grow alone in the gravel. We are considering retrofitting a skimmer and a water feature to filter the water additionally.

Design: The water is circulated under gravel by four bubble pumps pulling water through pipes under the bog area and aerating the water. There is no additional filtration system.

My question: since the issue seems to have been caused by nutrient run off and leaf drop will a 100% water change out solve the issues (we had no algae in the first year)?

Water quality - unknown (do not have a kit)

* Ammonia Level (pond)
* Nitrite Level (pond)
* Ammonia Level (tap water)
* Nitrite Level (tap water)
* Ph Level, pond (If possible, KH, GH and chlorine)
* Ph Level, tap water (If possible, KH, GH and chlorine)
* Brand of test-kit used and whether strips or drops?

Other useful information:
* Water temperature? - very warm in shallow zone (12" deep) usually a couple degrees below day time high
* Pond size and how long has it been running? 45'x35' with 12'x24' 6.5' deep zone; approx 70,000L
* What is the name and size of the filter(s)? bog only
* How often do you change the water and how much? did one 50% water change this spring
* How many days ago was the last water change and how much did you change? 1 month; 50%
* How many fish in the pond and their type? no fish; lots of frogs, bugs etc. wildlife also visit occasionally
* What kind of water additives or conditioners have you used? hydrogen peroxide (1L @ 3%/1,000- L)
* What do you feed your fish and how often? n/a
* Any new fish added to the pond recently? n/a
* Any medications added to the pond? n/a
* List entire medication/treatment history for fish and pond n/a
* Any unusual findings on the fish? n/a
* Any unusual behaviour like staying at the bottom, not eating, etc.? n/a

First spring (2019). Many plants did not survive the winter freeze. Also we did not understand the importance of potting/fertilizing plants. We had significant leaf drop in fall 2018 and spring run off from ground into pond in spring 2019. The tree has now been removed and drainage improved so we did not have these issues in spring 2020. I vacuumed out the leaves and silt (run off) in spring 2019.

View attachment 129635

Late summer 2019. Warm water at this point was contributing to massive string algae. We tried to increase our plants (harvested from local water ways). We still were not potting/fertilizing. It was a losing battle...

View attachment 129636
Algae was choking out everything.
View attachment 129642View attachment 129641
and clinging to the walls
View attachment 129637
some visitors in fall 2019 (you can see heavy string algae even with the cooler water)
View attachment 129638
Spring 2020 crystal clear and COLD water before plants came up
View attachment 129643
String algae was back with a vengance once the water started to warm up in may. We have added many additional plants and many potted lillies since the photo was taken.
View attachment 129645
I swear I saw this pond on a website that was like " top 10 creative swimpond ideas" :)
 

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