Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Filtering / cleaning the water in a 1/2 acre lake

Hello.
We are new to lake / pond ownership.

We bought some land with a 1/2 acre pond that was in desperate need of silt removal. So we drained it and got it back down to a solid clay base and now it's filling back up.

We are going to introduce bottom up aerators and have put mesh filters in the streams that feed it.

Our biggest problem now is the colour of the water. It's like a brown colour and we think it's tannins in the water from the streams and ditches. We have put mesh filters in the ditches that feed the lake to stop large leaves and twigs. But looking for something to clean the colour of the water (we believe is tannins)

Thank you

Can you have a sample analyzed?

Test the pH of your pond to see if the tannins are an aesthetic or an impactful issue. Only specific mediums can filter tannins out of the water. Tannin usually comes in the form of fumic acid or humic acid, so if the tannins are an issue, you will have acidic water.

A simple, easy to use pH test will tell you everything you need to know. Also, just to be sure it is tannins, put some pondwater in a glass, let it sit for a few days and if it remains tea colored, it is probably tannins. If it clears, it is probably suspended sediments.

Rob, I had tannin issues from big oak trees that I put in the bottom for structure. The tannins came from the fresh cut and dozed oaks. The water turned black and killed everything that I stocked.

Have it analyzed.

Thank you for all the replies.

I will be able to test PH when i get back. But that is the only tester i have to hand.


I have let the water settle in a bottle its still tea coloured a week later. (very very very minor little bits at the bottle, Like 3 - 4)

If the colour of the water is not a problem then thats fine. But i just don't want it silting up the lake again in a few years.

I was wondering if i could add some kind of filter media maybe stones or something in the steam to clean the water before it enters the lake.

Rob, realistically the answer is, No. Sure, in theory you could pass all the water through activated carbon or polywool but those are impractical remedies. Almost everything solubilizes in water, its an amazing medium in that regard.

You can devise methods to keep large debris out of your water which are practical or you can filter the water in your pond like a pool. I wouldn't really advocate either of those solutions. If you do use rocks as you stated, do NOT use concrete rip rap!

Whenever a watershed is the main source of water for a pond there is only one solution to have any control. First, slow the water down before it reaches the pond. Secondly, only allow water from the top of the water column to enter the pond. In fast water, turbidity is scattered throughout the water column. In slow water, turbidity is concentrated lower in the water column.

Please note, this advice is based on zero information about your ponds ecology.

Just tested the pH it's 8.02

We do have an option to control when the lake gets water and when it flows around the lake.

So maybe is it an option to filter the water in the lake rather then keep intruducing tea water?


Thank you

If your pH is 8, that is acceptable but its not what I expected. Something is going on in your water you're not telling or you aren't aware of.

Just to be sure...

Take a pH sample at sunrise and another at sunset. Typically, pH is highest at dusk and lowest at dawn. This is because nighttime respiration increases carbon dioxide concentrations that interact with water producing carbonic acid and lowering pH.

Thanks for the reply.

That ph was taken very close to sunset.

Could it be anything to do with the amount of fields surrounding us and the chemicals used on them ?

I'll give you as much information I know hoping it will help

1/2 acre
Completely clay bottom
10-12ft all around
Fed by one ditch / stream (mainly rain and field run off)
8.02 pH sunset
8.40 pH sunrise ish

No aeration yet but have it ready to go in.

Metal mesh filter to stop twigs and leafs coming into lake from stream

It's now filling up from 2 months empty

It had 3-4 ft of silt all around the bottom

There is a funny gone off smell coming from the lake


Hopefully these answers any questions . I'm unsure if there anything I'm forgetting or don't know.
Would their be anything specific I may be forgetting or not know about.

What kinda place should I look for to get it analyzed ?

We did have it analyzed before but think they looked at it more as safe for swimming or not


This is what that reason said.. probally not relevant


This test was done before we cleaned it out. There was talks in the village of it being contaminated

Heck, analyze it yourself. Get a bucket of pond water. Add minnows. See how they do.

I wouldn't be worried about anything at this juncture, other than your shoreline. Now is the time to start planting native grasses around your pond. Choose grasses with expansive root structures that hold soil. What you plant around your pond is just as important as what is in your pond. You're in the UK and I have no knowledge of your native flora.

You may also want to observe the farming practices of the field behind your pond. What that farmer does to his field, will end up in your pond. I recommend a 50 foot native grass buffer around a pond but it's rarely observed. 15 feet at minimum.

The "off smell" from your pond could be remnants of the anaerobic silt that was removed. I am sure some hung around and now that it is exposed to oxygen, its beginning to break down. It probably smells of excrement or a dead animal.

I wouldn't worry about comprehensive water testing until your pond has been full for at least a year. I would recommend an inexpensive, about 30 USD, for a multipanel test kit. At the very least you want to measure pH, ammonia, phosphate and nitrites. Chart these on an excel spread sheet along with weather information when the tests are conducted. Also, for about 50USD, and this is a must, a dissolved oxygen (DO) testing kit. DO meters are rather expensive and require maintenance but in my opinion, it was worth it. A less expensive test kit is adequate. Last, a secchi disk. A healthy pond has visibility from 12-30 inches. Below 12 and you have some type of bloom issue. Under 8 and you have issues. Over 30 inches, you have a sterile pond.

Once water is added to your pond, it begins what is known as the "Nitrogen Cycle". Although it begins immediately to an extent, I suggest one year before adding your primary fish. This is another rule no one follows. Add your baitfish, let them complete your nitrogen cycle and reproduce as forage for your primary species.

Last but the opposite of least is your primary fish species. All the data you collect in a the year before adding the primary species, dictates the type and quantity of fish you should put in your pond. I suggest not being adamant about one species over another and never adding so many fish to your pond you have to feed them. On this I am in the extreme minority. I believe in a balanced pond ecosystem, like a natural body of water, some people prefer a, "Job Pond". The choice is yours and yours alone.

Postscript; Here in the states, the Universities are great resources for empirical data and scientific understanding. The best part, they always help me for free.

Joey, agree somewhat but only somewhat re primary species. Most of us look for the ever elusive balanced pond. Meaning a balance between predator and prey which generally lasts about 15 minutes in the life of a pond. But, we keep trying once we define our goals.

A predator needs prey that is between 1/4 to 1/3 its size. And, that prey needs to be healthy. High protein feed gives us the best bang for the buck. The feed consumed by small healthy fish thus is converted to protein by the bigger predator(s).

So, the fathead minnow feeds the sunfish that feeds the bass. Any interruption in the chain affects the entire chain. So, I toss high protein groceries that takes pressure off the smaller part of the food chain along with the bigger members.

BTW, none of this stuff works if the water isn’t healthy(balanced environment).

There could be a few reasons for over 30" of visibility, and not because the pond is sterile.

I agree, Dave. Thank you for the alliteration.

I apologize eeshup, "sterile" was incorrect, "Nutrient Deficient" would have been more apropos. Only SWFI water is sterile and deadly. Pardon the faux pas....

Joey:

I have seen ponds that had a tremendous amount of vascular plant life and the visibility has been over 6 feet. Plenty of nutrients in there, they were just tied up in the plants at that moment.

To chime in here, somewhat on what I have learned reading here, is that regardless of a cleanout to the clay, there seems to be quite a lot of nutrient still around the pond basin that will fertilize the water column. Dissolved in the clay? Debris mixed in with the lay? Don't know. Coloring of the water could be any number of things, and as suggested... give it time and it will likely change.

But foremost, I think adding aeration to the pond, if possible, will get it to settle sooner for fish introduction. Assisting in breaking down the remaining anaerobic material still in the pond basin and will reduce further muck accumulation in the future.

Lastly, liming the pond should help with health in the long-run if performed in moderation. Increased alkalinity will lower the effectiveness of tannins in changing the PH by buffering against PH changes. I think it will also reduce the effectiveness of tannin on changing the color, but that is only an observation theory. You could test this with your bottle test.

If you are concerned about silt and runoff filling the pond again, some have built a silt catch pond up-flow that is basically a sacrificial pond which is easier to clean than the big pond. Some call these forage ponds in which small fish are raised. I would love to do this myself, but being on a hill makes this a bit challenging.