Hi all, I've been reading over the forum and the content is amazing thanks very much for all your help! That being said I can't seem to find some info, so here is my project and conditions.
I've had an old lake excavated down to a mix of clay and clay/gravel, pretty clean stuff that leaves no grey silt when messed with.
5 acres in size, kidney bean shaped.
average depth 7 feet, down to 10/12 in areas.
trickle stream in from upper ponds that I can control.
Some spring input
Water goes from cold to warm when swimming in it, not sure if it is spring action or just deeper colder water being churned by wave action.
DO testing shows 4ppm at 2 feet down and 7ppm at 6 inches down, 3 years ago before i excavated I tested the lake in the winter and was getting 3 to 4 ppm under the ice, 7.5 ph.
PH currently shows 7.5
Very little to almost no weeds.
I've introduced about 500 sunfish and a few thousand minnows to it and i can see the swimming around and hitting bugs etc.
I've refilled the lake after it was excavated from a massive upper pond that has lots of tannins in it, my new lake is very dark which I suspected would happen and also expect it to clear out after the first and second winter with fall rain/winter snow/spring melt off.. Before the lake was excavated it was crystal clear....but the otters blew the dam so it was time to rebuild everything.
So, that's the history and now I'm wondering about aeration. Because this lake is so new but with tannin rich pond water can I safely aerate it from no on? I'd like to start the process so I can keep the ice off part of it this winter for photosynthesis and to give what fish i have in there a helping hand.
And, should I place the diffusers at about half depth as to not turn over the depths in the winter?
Are the tannins going to be affected by the aeration and in turn affect the fish?
I have a 270W panel, large airpump, controller, diffusers etc.
I have seen many discussions on Pond Boss about avoiding getting tannins into your pond. However, I do not recall a thread about getting rid of tannins once they have become a part of the pond water.
Tannins are large organic molecules (since they come from plants) and the chemistry gets very complicated very quickly.
I am speculating - but many large organic molecules are susceptible to oxidation which breaks them down into smaller component products. I am not aware of any break-down products that are worse than the original tannins, but I am NOT an expert.
You might try a simple experiment using a small aquarium bubbler. Put samples of your pond water into two jars. Put them both in a dark place and run the bubbler in one jar for 24 hours. Then compare the color of the two jars. If the bubbler jar is lighter, then you may have broken down some of the tannins.
If you really wanted a good test, then put the same number of minnows in both jars and confirm that the minnows in the bubbled jar survive at least as well as the ones in the other jar.
If the bubble test proved to break down the tannins, then starting aeration in your pond should have multiple benefits.
Otherwise, time and further inflows of water should reduce the tannin content of your water.
P.S. It is a good sign that your sunfish and minnows are apparently surviving. However, I would certainly feel more optimistic about adding expensive stocked fish after the water has cleared.
When I built my lake in early 19 I had a lot of timber and brush piles in the back end flood over because the pond filled waaay faster then I thought it would, I figured I would have close to a yr to remove it but the pond filled up in 6 months, wet yr.
Long story short, I wound up with a lot of tannins in the water for several yrs, water was real brown, low viability. It didn't seem to hurt anything and the fish seemed to be fine, I stocked it just like normal recommendations, it has since then cleared up a good bit, granted it has a good bit of water going thru it, about 120 Acres of runoff in a 15 surface acre lake, but it has not had much runoff at all for the past 12 to 14 months, and its as clear as Ive seen it.
Every body told me I would have a ton of problems with it, to the point of 1 guy tell me, under similar situation in his pond, he wound up having to completely drain his lake and remove the oaks. Mine was all oaks, tree tops from logging and firewood, including a lot of standing oak timber, in the back shallower coves.
I consider myself to have gotten lucky to not have any residual problems from it, I have had several very knowledgeable people say I would have but so far so good. by the time I was told it would be a problem it was too late, the pond was already full and I had added a lot of dollars worth of stocking fish, I was prepared for the worst but its been ok. visibility currently is probably 3 to 4 ft.
Good Luck!
All the really good ideas I've ever had came to me while I was milking a cow.
There are multiple "tannin reports" on Pond Boss that are binary. Either, most of the fish died when the oak brush piles got flooded, or all of the fish appeared to do just fine.
I have personally caught LMB from tiny ponds with black water where the oak forest was encroaching on the shoreline so closely you could barely cast. Yet other people have reported that when their pond picked up a light stain they then suffered a large fish kill.
I suspect some aspect of the pond water chemistry affects the tannin molecules and renders them inert in terms of harming the fish in some of the cases. However, I have never read on Pond Boss (or elsewhere) what water factors are important in determining tannin toxicity. That would surely be a useful bit of information to have!
Rod, in those ponds where the tannin appeared suddenly and the fish died, the tannin could have disrupted the amount of sunlight getting to the plants in the pond. Enough could have died to create a low DO event and that's why the fish died. Up in the Northern part of the US there are heavily tannin stained waters and the fish do fine. Those lakes don't have high fertility, and don't have a high fish population either........
I have never observed a tannin fish kill or had a direct buddy that suffered one. However, there are Pond Boss "regulars" that say they have suffered a fish kill, and tannin fish kills are generally in the public literature.
I feel like we are missing some key element that is also part of the tannin fish kill mechanism. I just have no clue what constitutes the mystery factor!
There are lots of non-oak tannin waters. Most swamps are much like that. One key is good alkalinity. Add ag lime to improve the water quality. Always smart to have a good buffer.
There are lots of non-oak tannin waters. Most swamps are much like that. One key is good alkalinity. Add ag lime to improve the water quality. Always smart to have a good buffer.
More good info!
However, the oak forest ponds I fished as a youth were where the Flint Hills (all limestones and shales) gave way to sandstone outcrops. I am fairly certain the soils for these ponds were acidic, even prior to any tannic acids introduced by the oak leaves and twigs.
I am still perplexed. (But that happens quite often while I am reading on Pond Boss!)
Thanks for the info everyone. I just did a few samples yesterday, PH 7.8, DO 7ppm, water temps 26 at surface 22 at 2 feet under. The water mixes warm and cold all over the lake - hard to stay in a warm spot for long.
I put a go pro under the water in a clump of old vegetation that is now submerged and it is full of sunfish, I was worried that the wee sunfish i put in about an inch long would be dead but they are all over the place intermingled with the ones up to about 4 inches. The full grown sunfish travel the whole lake.
We have now put about 3000 minnows in the lake about half and half dace and FHM along with about 100 mud minnows, I wasnt seeing any of them in the big area until yesterday - the whole shoreline all around the lake is alive with new tiny minnows - seems that they have been busy....
One thing I notice in the underwater cam is the amount of plankton is crazy, giant waves of it in the water column.
I've just set up my solar aerator system to keep the ice from forming this winter in one end....ill post pics.
In your original post, you said almost no weeds after the renovation. That pond shot looks very mature and fertile. Is your video from a section that you did not disturb during the renovation?
Also, a lot of the "color" in your pond water may be due to phytoplankton and even zooplankton. I am hoping your tannin content will not be significant.
I am NOT an aeration expert, but IMO aeration would be a benefit to your pond. I am more worried about a fish kill under the ice as your fish mass in the pond increases. I think an aerator in shallow water during the winter might save you some future mishaps. (I assume you sometimes get heavy snowfall on top of 100% ice cover.) If all of you aquatic plants and phytoplankton die off due to lack of sunlight, they will consume most of your pond oxygen as they decompose.
P.S. There is a chance that I turned your aeration post into a "tannins" post when I tried to answer that question. If you are still contemplating aeration, perhaps you should type a new post and just discuss the particulars of your lake and your northern location, and see if you can get some good aeration system advice?
Yes there are a few little patches of submerged vegetation left over and they swarm around it.
I have just set a solar aerator up and it's up and running, for sure Ill be keeping it going thru the winter. I bought a VIVOSUN 55W Commercial Air Pump and it seems to be working well for now, runs off a 270w panel and 2 trojan batteries with an invertor....can't hear it.
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