Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Potassium demand test for pond treatment

Tomorrow (the day after Thanksgiving) I'm going to treat my trout pond with Potassium Permanganate to see if I can clear the water by killing the phytoplankton that is coloring the pond a Coca-cola brown. In the nine years I've had this trout pond I've never seen this brown of water. It's not a plankton die off that is normal this time of year as there there typically isn't much phyotoplankton in the pond anyway due to it being flow through most of the year. Bill Cody has identified a heavy bloom (27 inches of clarity) of probably the genus Ochromonas which is a "yellow/green" algae and had been associated with fish kills although not proven to be the culprit.

I've had problems with the brook trout in the pond this fall with stress, which has led to some fish succumbing to bacterial disease -- most likely an Aeromonas or Pseudomonas variety. It's also not uncommon with brook trout vs. brown or rainbow trout.

Antibiotic treated feed got a so so response, however, in all honestly I should have a test done to determine exactly what bacteria I'm dealing with, and which antibiotic is most effective to treat it. Unfortunately there are no fish certified vets in Indiana except those at Purdue University, and it's been problematic to get a live fish to the university several hours away. I was set up to go one morning with our "good vehicle" complete with aerated tank, but I wasn't able to collect a specimen.

Anyway, it's possible that if I'm dealing with a gram negative bacteria the PP could knock that back along with killing the phytoplankton that is coloring the water a dark brown, which shows no signs of leaving. See photo below. Also if parasites are involved the PP may deal with them also. I don't have much to lose as there are only about 30 or so fish left compared to the 100 I planted last fall. I'm looking at this as a learning experience, and if it helps so much the better.



There are two ways to go about this: One is to apply 2 mg/l of PP to the pond (2.7 lbs. per acre/foot), and if the water stays pink for 8 to 12 hours you're good. If it turns brown before that there was enough organic matter in the pond to neutralize the PP before it became effective. Of course on the other hand adding too much can not only waste the chemical, but also be detrimental to the fish in the pond if one over does it.

A better method is to determine "Potassium Permanganate Demand" depending on the organic load of the water by using samples of water, and calculating how much one would need depending on the volume of the pond. Here's how it's done and how I did it, which by the way I got the information here:

http://edis.ifas.ufl.edu/fa032

First as per the PDF I made a stock solution of 1 gm. of Potassium Permanganate per liter (1000 ml) of distilled water. I didn't have any beakers or anything to measure milliliters in so I used a quart canning jar that was marked up to 800 ml and poured that into a cutoff 2 liter clear pop container. I measured another 200 ml out and added that to the 800 ml to make 1000 ml or 1 liter.

Here is 1 liter (1000 ml) of the distilled water before adding the PP:



Here is the same distilled water with 1 gram of PP added to make the stock solution.



I transferred stock solution to a canning jar (the canning jar wasn't quite 1 liter), as I needed the pop container to add 1 liter of pond water to.



Here's a 1 liter (1000 ml) sample of pond water (on the right) before adding 1 ml of stock solution. The tape marks the liter mark. One waits for 15 minutes and if it turns brown in the 15 minutes it's not enough. If it stays pink one multiplies the ml added by two and this is the minimum concentration added to the pond.



Here is it is after adding the 1 ml of stock solution:



Here is is after 15 minutes. It has turned brown so the 1 ml added means 2 mg/l application to the pond is not enough.



I next tried adding 2 ml to another liter of pond water and it stayed pink which means 4 mg/l pond treatment is enough.



However I decided to add 1.5 ml to see if 3.0 mg/l was enough as I don't want to add more of the chemical than I have to. It turned out the 1.5 added stayed pink so 3.0 mg/l treatment to the pond is enough so i will go with that.



2.7 lbs of PP is needed to make a 1 mg/l treatement per acre/foot. Since the pond is 0.5 acre feet I need to add 1.35 lbs. per mg/l. 1.35 lbs X 3.0 mg/l = 4.05 lbs. or 4 lbs. 1 oz.

Later Edit: My new fish health textbook I just got for an early Christmas says to multiply by 2.5 the ml's used instead of 2 for the mg/l treatment of the pond for bacterial issues. That makes the amount used come out to about 5 lbs. vs. the 4 lbs. 1 oz. I've got about 5 lbs. so I'll just use it all.

Wow Cecil:
You are like the mad scientist of the Fish/Pond World. I can't wait to see if your idea(s) work. Your ponds and place looks cool.

I've used Potassium Permanganate for iron filter recharging, school locker room foot staining, and oxidizer, but I've never thought of using it to clear a pond.

Potassium Permanganate is used for a number of aquaculture water fixes. See the link Cecil posted. It is often used to sanitize (for lack of a better term) ponds with problems. Hydrated lime is also used but is different and not as versatile (cure as many problems).

Cecil:

LMK if you need more PP measured out. For anybody interested, I don't have a gram scale, but I do have an electronic powder measuring scale that measures to 0.1 grain. Since 1 gram is 15.4323584 grains, I rounded it off to 15.4 grains and weighed out that much for Cecil. I have some small plastic screw-top specimen vials that are waterproof, so the 1 gram samples were put in those vials.

Mad yes. Scientist not so much.

Thanks for the kind words. That's actually not that great a property pic. Can you see what my dad did with a few of my fish cages to protect his Quince trees from the deer?

The oxidation of organic matter is its mode of operation.

Scot,

I only needed a one gram sample for the stock solution so I'm good to go. Thanks a bunch! I'm going to have to get a gram scale at some point. I also want to get a microscope too. I got an awesome book for Christmas that shows me how to set up my own pathology lab. At one time I tested milk in a lab so I have some experience with bacteria cultures. With no vets qualified to test fish in Indiana except at Purdue, I'm going to have to become self sufficient.

Cecil,
Check with a LEO. Sometimes they confiscate scales from drug busts. That's where I got mine.

I'll have to ask. I have several customers that are LEO's and a couple of friends that are.

Cecil, the test methods do not take into account the PP absorption by the organics on the bottom. Hopefully the amount from your calculations will be enough to keep the pond pink long enough to get the job done. After application and mixing, if pink does not persist you will know why - absorption by benthic organics.

OK you guys:
I see that Esshup fits right into that mad scientist category as well. Wow, you guys are into it! Now thank you Cecil, I have some new info to question Fav Guy about (PP-like, hmmmmm, is this legal in Michigan? Have you ever used it?, would it help our crappy lake that has been green for about a month now?- does it work at 50 degrees and below, hmmmmm Fav Guy?) which gives me an excuse to e-mail him sometime week.

You know I thought about that Bill. Not sure what to say but the publication above seem to indicate a demand test for the water will do the job.

According to the publication another way to do it is to add 2.0 mg/l, and if the water does not stay pink within 8 to 12 hours to add another application. We do know from the demand test 2 mg/l would not be enough.

Perhaps the problem is adding enough to potentially negate absorption by benthic organics could be too stressful on the fish???

I would think adding PP to a lake your size would be cost prohibitive especially if you don't need it. And IMHO you don't need it. I doubt it's illegal though. The FDA even allows it's use with food fish.

Personally i would take green water over this brown crap (actually yellow/green algae), and the fish stress and subsequent disease and deaths I have any day. I can't say the algae is the culprit but this is just not normal for this pond so it's just not a matter of aesthetics. Trout do best in clear water also.

Your green water means you're getting some nutrients somewhere or nutrients already in the lake are getting recycled when the lake turns over as it probably did this fall. How many people fertilize their lawns on your lake?

Another thing to keep in mind: We all want crystal clear water. However, one of the Catch22's of crystal clear water is you get lots of light penetration and if you've still got a fair amount of nutrients coming in you can get explosive macrophyte (weed) growth if the nutrients aren't being uptaken by phytoplankton. I know this from experience in my biggest pond!

BTW PP is used as a neutralizer for rotenone if you have water downstream that has fish you don't want to kill. They will be using both chemicals in the fish kill in the canal leading to Lake Michigan where the carp problem is.

It is wierd Cecil, the lake was at 4'2" clarity on Oct. 10, then we had rains and lost it all again, down to 2'8" by Oct. 31. It is all a function of run-off. None of the other lakes look bad at all. It is these storm drains. We banned phos. use in fertilizer this year. We are the only Planktonic algae lake, and the only lake without any vegetation. We know the carp are still in here and spawned too.
GF Lakechair is in Flint, brought her mom home with hospice care last week, so there is no info on fish kill II, communication is at a standstill right now.
I would freak out with brown water, the green is bad enough. It is sunny today, will go out with the hip waders again, getting the leaves out -makes me feel alive to be out in that water, even when it is crappy.

The storm drains most certainly could be the reason for your lack of clarity and of course the sediments coming in could fertilize your phytoplankton giving you the green water. The green water is uptaking your nutrients and blocking out sunlight so you don't get any macrophytes. Actually that's what fish farmers and many pond onwners strive for but it can be tricky to achieve.

Update 11/28/2009 Potassium Permanganate Appplication to the Trout Pond



Water temp just before the start of the PP treatment was 44.6 F. Seechi disk clarity was the same as two previous checks in the last several days at 26 3/4 inches. D.O. before start of treatment was 11.39 mg/l.


Getting ready to mix the PP for the trout pond treatment. I weighed out 4 lbs. 2 1/2 ounces which minus the container comes out to 4 lbs. 1 oz. or a pond treatment of 3 mg/l. Excuse the messy counter top. It's my taxidermy workshop/pond workshop and a disaster today.



A dust mask to keep from inhaling the PP powder while weighing. The PP powder is very light weight and bad stuff if it gets into your lungs.



Items needed to apply the PP to the pond: A 30 gallon trash can, boat oar to mix the PP powder with the pond water, the PP that was measured out covered with plastic to keep it from blowing out, protective chemical gloves that reach to the armpits (I used to do a lot of deer hide tanning), and a pitcher to throw out the PP solution out over the pond water. I used safety glasses not pictured. PP can do serious eye damage so I wasn't taking any chances. I'm glad I did as I got a splash on the eyeglasses. This stuff will stain your skin brown if it makes contact. Fortunately that didn't happen.



4lbs. 1 oz. of PP added to the pond water in a 30 gallon trash can. It looks like grape juice! After the first application I had residue left in the garbage can and filled it again with pond water and applied this. The the garbage can was rinsed in the pond.



Pond water after application:







Same pond water in a white five gallon bucket:




Kasco aerator running on top of the diffuser bubble (not shown) to help mix the PP in the entire pond to eliminate hot spots. Note the pink tinge. As cold as the water was I wasn't concerned about D.O. depletion to dangerous levels due to killing the phytoplankton. But that can be a concern in warmer water.




So far no dead fish and the bluegills in the cage seem O.K. I did see two brook trout come up to the surface briefly but go back down again.

Sorry, Cecil, I can't take it anymore.

KMnO4

What?!?!?! Doesn't everybody put PP in their pond??

Update: The KMNO4 was NOT a big hit with the trout. All 32 except one tough individual are sitting in the bottom of two freezers and the upright shelves of another freezer ready for ice glazing, vacuum sealing, and then for sale to taxidermists.



What's odd was the pink color didn't even last two hours! Like Dr. Perca surmised the bottom organic matter may have caused the KMNO4 to be spent before the optimum 8 to 12 hours. Or perhaps the iron in the water may have done so also. The weed growth I had may have been dying off due to the lack of clarity. Regardless it may not have been enough for the pond but apparently it was too much for the fish!

This is not the disaster it appears to be. I can still sell the fish and some are quite nice at over 19 inches for only 2 year old fish. It would have been nice though to grow them out one more year in the 22 to 24 inch range. That's a 5 to 8 pound brook trout!

I was having problems with them and had doubts it it would be worth continuing with what turns out to have been a 68 percent mortality rate in a year's time. Apparently I need water about 5 degrees cooler in later summer with NO iron to irritate their gills. Browns and rainbows I have no problems with but brooks are more sensitive. Additionally it may be possible these brooks came with some bacterial disease baggage vs. other brooks I've had from other sources.

I think I'm going to concentrate on other species now especially ones where I don't have to run the well 24/7 for several months a year.

Last I checked the small bluegills in a cage in the same pond seem to be all right. If not I have more.

They're really pretty.

The feed from Aquamax with the Astaxanthin added really colored them up didn't it?

Here's a fresh one right after it was netted.



It's a shame I couldn't keep them for a year or two more. They would have been monsters.

The last 2 year old brook trout I got from the Indians were only 6 to 8 inches. Imagine that, 6 to 8 inch 2 year old brook trout vs. 16 to 19 1/4 inch 2 year old brook trout. Life span is supposed to be about 4 years for domesticated brook trout.

Some day in the future I may consider a much, much, smaller pond with a liner and possibly less flow, but since the pond would be smaller it would be easier to keep it cooler. More exchanges too. And of course some kind of an iron filtration. Reduce any stress and start out with treated eggs to eliminate an possibility of aeromonas or pseudomonas bacteria. Another possibility is to produce triploids by temperature shock and it's possible they wouldn't get stressed at spawning time. Of course the downside to that is triploids are more sensitive to environmental stress.

I could grow them out in tank or raceway too but the fins are not usually in as good condition vs. ponds.

Cecil:

Sorry to hear that. Those colors are amazing! Now what are you going to do with the pond??

I'd like to drain it for the winter but I still have the bluegills in a cage in it. And I can't move them to the RAS as it's not cycled yet. I'm afraid to put them in the big pond as some are borderline for staying in the mesh. I want no escapees and subsequent reproduction of bluegills in the big pond and worked hard to keep it that way.

I may use it as a spawning pond for bluegills, pumpkinseeds, or even in a couple of years possibly smallmouth bass. Do you have any suggestions Scot?