Pond Boss Forums GENERAL QUESTIONS Help Need help with a turbid pond

Hey everybody, i'm new around here but from the looks of it this is the place I need to be to find answers.

I've been living in Cambodia with my family for a few years now and I opened up Cambodia's first wakeboard park. We use it to help marginalized fathers lead their families well.

I found this awesome little spot with these palm trees next to a little rice paddy. The rent was cheap and the land lord likes me so I pulled the trigger on renting this little spot out. After a few weeks of learning how to drive an excavator I finally have this little rice paddy holding water. It's a little over an acre large and an average depth of 3ft. It has a clay bottom and the turbidity is really bad. 1" visibility maybe.

I also am fighting off increasing e.coli levels. I do have a few little TP in there but I don't think (although I really have no idea how many I would need) enough to fight off unhealthy bacteria levels.

Really the only thing I'm using the pond for is recreation.

Can you guys and gals help me get better at managing my pond?

Thankfully yours (totally new to the pond game)

-Alf Evans

Hi Alf,

Welcome to PBF. My first concern would be the E. Coli. As you probably know it is a bacteria commonly found in human and animal waste. I would spend some time figuring out how it got in the pond and correcting that situation first. If you can't eliminate the source of the contamination, the pond may never be safe to swim in. Just my 2 cents.

Good luck,

Bill D.

Welcome to the forum!

Agreed on the e coli thing.

To reduce the amount of turbidity, it's probably an ionic imbalance in the pond. If no fish are present, and it's not a mechanical issue (many fish stirring up the bottom, or cattle stomping about) then an aluminum sulfate treatment would help. There are 2 great threads in the muddy water section that explains it.

If you can get an aquarium water test kit, that will help. You want to test for alkalinity, pH and hardness at a minimum. That won't help with the bacteria, but that will give you a starting point on fighting the turbidity.

Thank you gentlemen.

I do have cattle near the location, but we've fenced them out. They rarely get to the lake anymore and if they do we run them off quickly. Could my 500 TP be causing the e.coli spike? If so is there anything that can counteract that, or do I need to get rid of the little fishies?

We dumped 300kg of crushed Alum in the lake two months ago, but didn't get much change in condition. We administered from a local rain water area as we don't have a municipal water source to make our slurry with. Could the quality of water that we made the slurry with have effected our alum administration process? We put the alum in over the course of two weeks. Here in Cambodia I think we can get it cheap, but we crush it by hand and then hand mix it in a 500L water tank…then pump it onto the top of the lake. It seemed to make a difference for a while, but it feels like the clay and mud has stirred up again. We have a pretty shallow pond and it is for recreation. Do you think a pond liner is needed?

Thanks for the thoughts gentlemen. You guys are a gold mine of knowledge.

The way alum works is that the concentration has to reach a certain stage before it flocculates and all the clay precipitates out. A different water source isn't needed to mix it, you can pump from that BOW into a barrel, dump it in, make a slurry and let it overflow into the pond. You probably will have to make a alum slurry, then a hydrated lime slurry, alternating slurries to keep the pH in check. Alum drops pH, hydrated lime raises it.

Alum doesn't do anything until the concentration reaches the tipping point. Then everything works in a hurry.

If the pond gets runoff from the land where the cattle are kept that could be the source of the e coli. I've never heard of it because of fish.

Hey Alf,

Just to add to what Esshup said...Not sure what you mean by TPs. If you mean tadpoles, or some small fish species, they are not a concern. The cattle do not need to actually defecate in the pond to cause the E. Coli. If they are near by and runoff from their area when it rains can get to the pond, they could be your problem. Anyway to locate the cattle downhill from the pond?

TP = Tilapia

Alf, now big are the individual TP?

I know they can sift through the pond bottom looking for food, but I don't know if only 500 would cause that problem.

Do a jar test and see if the problem is mechanical or ionic.

Thanks for the clarification. Folks in Illinois have heard of TP but never seen a live one. TP, dragons and unicorns are all banned by law as invasive in Illinois.

Our pond is located within a birm that the cattle actually have to get over to get in. And we have a fence (that they have recently been busting through) but we run them off as soon as we see them. Unless those boogers are coming in at night, or my employees are allowing them in when i'm not looking (which is a possibility) I don't see how it's getting in there. There is no water shed at our location…unless it floods. Our lake surrounded by a 5-6ft elevated dirt birm. Is there a possibility that the water from a cattle ridden pond directly on the other side of our birm is seeping through? It's lower than our lake so I wouldn't think it could intake that water. Does e.coli grow with sunlight and algae in the lake?

Regarding the Alum. If we have continuous recreational traffic (i.e. people playing in the water and stepping on the bottom) is it worth it to even worry about the alum, or will the concentrate continue to cause the clay to sink to the bottom even after it has been stirred up?

80/20 rule in effect here for Pond Boss. I've been here one day and received more good intel than I ever did from looking on google. Thanks again everybody.

That's the amazing thing about this forum. We are a diversified bunch, and are more than willing to help.

Yes, mechanical stirring/turbidity will happen on a daily basis if there are people in it, but to what extent it will create turbidity I don't know. Rex (Rainman) is better versed in dealing with alum and turbid waters than I am. But I do know that if the level of alum in the pond is great enough, the clay will precipitate out again. How fast? I can't answer that, but it would be nice if it could happen overnight. I.e. start with a clear water pond in the morning.

There are solar powered electric fence chargers. One of those, and an added wire or two to the existing fence might help stop the cattle from breaking through. There are ways to have gates in the fence that are not "hot".

I will throw this in as an FYI. There is a state park near me that has a swimming pond, separate from the fishing lake. During hot summers when swimming load is heavy, they have E. Coli issues and have to close the swimming pond. The source of the contamination is human. They ban swimming and time kills off the E. Coli. My understanding (and I am not a doctor) is E. Coli propagates in the digestive tract of humans and animals. Expose it to a well oxygenated pond and it will die. Again, I am not a doc and do not profess to be an expert in this area at all. Just relaying what I have read.

Hi Alf, and welcome!

I'll speak on your Tilapia and turbidity issues, since I happen to know a fair amount about both.

As for turbidity, as mentioned earlier, do a jar test first. Take a clear glass jar and get a sample of water from about one foot deep. Seal the jar and put it in a dark room for 3-5 days. If the water clears, something mechanical, fish, wind/wave, or animals are stirring up the sediments and mixing them into the water.

If you have 500 Tilapia in only one, 3 foot deep acre of water, AND if you do not have predators to eat all the tilapia babies, the Tilapia could be causing the turbidity, and maybe even the e-coli spike. That many tilapia need a lot of food, and without algae or sunlight penetration to grow plants, the tilapia are going to dig in the bottom in search of food.

With normal spawning, your 500 tilapia probably became 50,000 in a couple weeks and numbers will increase exponentially without a predator.

I know catfish are popular in Cambodia. Are the also catfish in the pond? If so, they root around on the bottom, stirring it up as well.

The 300Kg of Alum is a good dosage rate for 3 acre feet of water, but it needed to be applied all at the same time. Spreading the treatment over a 2 week period made the application almost useless. Alum does not dissolve into the water unless the pH is 5.4 or lower (a dangerous pH level). Use the pond water to create the slurry. There is no need to use clear water.

Bill D, in response to your comment regarding humans and e.coli. The e.coli only comes from defecation, yes? I mean I did have a big event recently and after that I had a decent spike, but I really don't think anybody crapped in the lake. But who knows!?

I figure we put the Tilapia in the lake 4-5 months ago and they were 2.5-3" long. Little guys. You really think we may have 50,000 by now!?

Should I introduce a predator to the lake? I do not have catfish in the lake, but I do have crabs and little shrimp.

What is the best way to make that slurry? We put the crushed up stuff in our 500L tank and stirred it by hand. After each empty tank we would see a little of the alum rocks on the bottom (the pieces we didn't crush up well enough) but I think we got 95% of that 300Kg dissolved into the water. Your recommendation is do it all right then and there as fast as possible?

Sorry i'm reviewing, it helps me to get it all out of the old brain here.

New question: I'm thinking about shocking my lake with Calcium Hypochlorite. If I understand correct this is used as a concentrated chlorine and would kill the e.coli. Is that a correct thought process? I'd love anybody's thoughts on that if there are administration calculations and administration procedures for that.

Next go round I think we're going to line the pond, and use a water well to fill it.

Thanks for the help everybody.

Just a thought....Easy enough to test if swimmers is the cause. Keep people out for a while and see if the level of E. Coli drops. If it does and then goes up again when you have another big event, you have your answer.

The concentrated chlorine will not be good for any fish or shellfish in the pond..........

Bill any idea on how long I should wait?

Bill, is that a "I don't swim in your toilet, so don't pee in my pond." type of thing?

Kind of like that. E. Coli is not killed by just washing your hands. Cleaning and sanitizing are two different things. After using the restroom and washing your hands, E. Coli and other bacteria are still potentially on your hands as well as other parts of your body that may have been contaminated. In the US food service industry, after using the restroom, employees are supposed to wash their hands, rinse in warm water, dip their hands in a sanitizing solution (like a chlorine bath) for several seconds and then let their hands air dry.

With a heavy swimming load in a BOW, there is a potential for this cross contamination to occur to a serious level with the water. People don't actually have to defecate in the water to contaminate it.


Alf,

E. Coli is an Anaerobic bacteria. Aerating your pond should help. How long it will take for the levels to drop I would not want to guess, too many factors involved. Again, I am not a pro. Do you have a Health Department there that could assist you?

Eye opener on that one! I always thought it had to be defecation.

That could very well be where our contamination is coming from then.

Thanks for you help guys. I'm sure i'll be back soon with more questions.

Just an after thought. Parents love to take babies and small children swimming. Those little folks have this tendency to "just "let er go" when the urge hits them. This could also be a contributor. In the US, tight fitting plastic pants over diapers are required in many areas.

Yeah, here it's a whole new ballgame when it comes to defecation and keep it to yourself. It's entirely possible that it's a human contamination after thinking about who and how often we have human traffic in the lake.

I love reading this thread right around breakfast time.

Bob, it could be worse. I could point you to a forum where chain saw accidents are discussed.......... Yes, there are pictures.