I have a 1 acre pond located in Southern Wisconsin. The pond depth varies from 12' to 2' having an irregular bottom with average depth probally 5-6 feet. The pond was constructed 2 years ago. The pond is quite clear being spring fed and has a 30 to 40 gal/min outflow. The pond receives no agricultural runoff and native oak woods are located above the pond which is then buffered by grass. The pond is stocked with bluegills, bass and a few catfish. Plant growth has been quite slow to establish itself it seems. Last summer we introduced some native plant species, Chara, Large Leaved Pondweed, White Water Lily to compliment the Pondweed and Chara that was beginning to establish itself. The pond is aereated with a windmill aereator. As the water began to warm last year we began to have some significant algae blooms appear. The surface would at times be covered with globs, although on windy days these would be isolated to the opposite shore. In addition the algae seemed to blanket the submerged vegetation and hamper its growth if not kill it. As the water cooled this fall the growth subsided but still was somewhat evident. There is still some growth this winter that can be seen through the ice. The algae growth hampers fishing and swimming.

I am interested in any ideas about controlling these algae blooms. Will they subside as the submergent vegetation more completely establishes itself? Are there any non chemical treatment alternatives? Does the ph of the water make a difference and if so can it be altered to help without harming the pond otherwise? I know chemical treatment would help but I don't know the long terms effects on the pond - maybe it would help the submergent species establish themselves which would in turn help minimize the blooms. I am not necessarily looking for a quick fix and would be interested in experimenting with anything short of chemical treatment if there is a possibility of something being effective. I am not against chemical treatment however if it is the only way to get the problem under control.

Thomas - You're to be commended for the detail and forethought shown in your post. Based upon the spring-induced outflows, your pond probably experiences a 100% "turnover" every 30 to 40 days. Such a dynamic pond may prove a challenge for fertilization programs, lake dyes or other non-chemical means of thwarting filamentous algae. I'm certainly not experienced with WI ponds - so DO solicit other opinions. But, I think your best options may be 1) physical removal of heavy filamentous algal growths 2) followed by CUTRINE-treatments to any remaining concentrations of growth on an as-need basis. The judicious use of CUTRINE shouldn't pose a threat to your fish or other desirable aquatic plants. One other thing (but also not in my area of experience): have you investigated the possibility of stocking tilapia? Since your pond is spring-fed, this otherwise tropical algae-eater might survive during the few months of summer in which your algae problems are at their peak. But, when water-temps drop below 50F, these fish are history. KD

-A piggyback question.

Other then tilapia is there an equally proficient cooler water species that will consume the filamentous algae? I have found varying minnow species that will eat just about everything else vegetation wise, (Except reeds etc.) but I can't get anything to eat the filamentous algae even if it is their only food source. (-Grass carp aren't feasible for me)

Thanks.

Pottsy - I'm unaware of any other fish specie (coldwater or otherwise) that would be an effective deterrent to filamentous algae. Tilapias, with their very prolific lifestyle, provide an excellent forage-base and some algae-thinning benefits. But, a low tolerance to relatively mild water temperatures and stocking-containment requirements (they're an exotic specie) are definite drawbacks for Tilapia.

You may want to consider nonflying ducks. I have a 2 acre pond that does experience complete water turnover several times a year which makes chemical solutions too expensive. I introduced Rouens and Black Swedish ducks and they have solved my algae problem as well as controlling duckweed and all the other weeds in the pond and snails. Of course you don't want too many ducks because they will cause several other problems for you. 5 or 6 to start with should give you an indication if you have enough for a 1 acre pond. As for timing, it took them until late summer to catch up in my pond (15 acre ft) and I am guessing that they will stay ahead of the curve this year. One other point, we have lots of wild critters out here and I had to build a raft to provide night sanctuary for them - coyotes, coons and bobcats love duck!

Someone will eventually bring up Israeli carp sold by Zetts in Pensylvania for filamentous algae control. These fish are a variey of common carp often called mirror carp. They are fertile and can reproduce like wild carp. They feed just like 'wild carp' by rooting in the sediments for food. They are omnivours which means they eat a variety of living and dead plants & animals found in the sediments. Their digging or roto-tilling and roiling of the sediments is the main feature primarily responsible for any algae control achieved. Only about 10%-20% of their diet is plant materials. Roiled, muddy water shades and supresses weed and algae growth. Digging activites sometimes digs up shallow rooted plants. Myself I prefer pond water without suspended mud. The fish will also eat fish eggs laid by broad cast spawning fish. Debate is out there if they eat eggs from nest spawners.

Good Post! I usually hear more from people worried about chemicals than with introducing non-native species to a pond. After doing fish sampling on the Mississippi River, I can tell you that just about everything anyone has put in a pond has escaped and somehow bred. Not all states are stringent on having sterile species. Big Head, Grass, Black, and Mirror Carp were all captured in our nets. What this will mean to the paddlefish, young of other fish, and what's left of our aquatic vegetation in the few backwaters left won't be good. Not to mention what Eurasian Milfoil, Curly Leaf PW, and Zebra Mussels are doing. Chemicals have been used for decades and have been under the microscope the whole time. If used sparingly and according to the label, a certified chemical applicator can definately maintain a healthy food chain and increase the users enjoyment of a pond or lake.
Robert B

Tom N. I primarily specialiize in natural pond mgmt. Your pond is behaving similar to many other new (1-3 yr old) ponds. Once filled and depending on the nutrient input from the watershed, filamentous algae is usu. abundant the first several years. It is impt to minimize nutrient runoff in the design/building stages and during early years by vegetating the sloping ground around the pond. You have done this with the 'buffered grass'.

Give the aquatic plants another year or two and when they inhabit about 30% of the pond bottom the filamentous algae growth will noticably subside. However you may notice early season fila. algae because the rooted plants have not started the new season's rapid growth.

Chara will very quickly colonize the entire pond bottom that receives sunlight. I do not like Chara in ponds. But the rooted plantings that are present should eventually crowd it into a sparse population. Chara however does compete heavily with filamentous algae for nutrients so the more Chara you have the less fila. algae that will be present. Ponds with bottoms compeltely covered with Chara usu often have no fila algae.

K.Duffie provides good advice in removing as much floating fila. algae as feasable. Its removal reduces nutrients in the pond and minimizes additional fila. algae growth. I usu. don't worry about removing fila. until it breaks lose and floats. Once floating it has basically "run its course" as a nutrient absorber and it is biding its time until it sinks/dies,and decomposes. If you have your nutrients under control and abated, the more fila. algae you remove the less you will have next year.

Bill C. Thanks for the post. This is good news.
My pond discharges into another pond (neighbors) which has a bottom completely covered with Chara and almost no fil. algae. I was hoping that as my pond matured that the algae problem might subside. How about cutrine treatment for a year or two? Do you think it will help the other plants establish themselves faster as the algae seems to cover them and seems to negatively effect their growth if not kill them.

Tom - I am not an expert on Cutrine. However, Curtine Plus both liquid and granular are algaecides. Chara is also an alga but a little more 'tolerant' to Cutrine applications than the filamentous algae types. The copper in cutrine will slightly supress the rooted plants but will NOT kill them. An early moderate dose of Curtrine may knock-down the fila. algae and stunt early season Chara growth before the rooted plants begin rapid growth. This technique can removing the early season, supressive algae problem. Cutrine is probably the more friendly algaecide compared to more popular types.

Do you have large-leaf pondweed or long-leaf pond weed (they are different)?. Where did you get it? In additon to the plants you now have, I would add some eel grass (wild celery) this year. You can get plants from Wildlife Nurseries, Oshkosh WI. You can also get them in the wild from local lakes. Eel grass will do a better job crowding out the Chara than the pond weed will.
1. What is the maximum and minimum water clarity during the ice free season?
2. Is your clarity stable or is it variable during the year since you pond is spring fed?
3. Do you feed your fish?
4. When does the filamentous algae become abundant?

Remind me this mid-spring to send you a jar for a sample to identify which algae you have when the growth gets blooming. A spring fed pond can develop cool water forms later & longer in the season than a typical pond. I'm guessing Oedogonium or Mougeotia.

Bill, I stocked Tom's pond, and it was Large-leaf Pondweed (Potomogeton amplifolius) that we put in. I believe that we also put in Eel Grass, aka Wild Celery (Vallisneria americana). I agree about the Chara keeping the algae in check, and I think Tom's pond will go through a natural process of maturing...it is a great pond with outstanding spring water flow.

Tom, I'd recommend spraying liquid Cutrine Plus on the surface patches. If it's a tough type, like Pithophora, you may need to mix in some Weedtrine-D or Reward. Don't spread granular Cutrine at this time, because it will drop down and hurt the Chara. If you'd like to hire a pro to apply it, I'd recommend Robert Burke, who replied above...he's a nice guy & will do a good job.

Did the lilies come up for you at the end of summer?

Mike Robinson
Keystone Hatcheries

Mike, thanks for the post. I was going to give you a call but before I got to it I ordered Pond Boss magazine and found this site and have been having fun getting everyone's input. I have contacted Robert by seperate E-mail and told him I'll give him a call when the ice goes out. Your suggestion seems to be the consensus. I will be interested to see how the plantings come up in the spring as the algae really covered everything by fall last year and seemed to effect greatly the plant growth. The lilies did come up and seemed to do well. Jim Loveless and I just hauled pea gravel and placed on the ice last week for bedding areas so that is all set for spring. The bass are now about 12 inches and bluegills about 5 inches so they did well over the summer, alas the trout experiment failed...Where can I get a good thermometer-do you carry them? I didn't see one in your catalog.

Bill C, thanks for the post. To answer your questions, water clarity is between 6-8 feet, which is fairly stable except after a heavy rain when the water clouds for a week or so. I do not feed the fish. Last year was the first year the pond was finished and the banks fully stabilized. The algae began to show up probally mid June; however I have a windmill aereator, which I stupidly placed the diffuser right on the bottom of the pond creating a problem with suspended solids which keep the pond cloudy until early June when I finally figured out why the water was cloudy. The algae shortly followed as the water cleared. As the pond cooled this fall and the days became shorter the algae problem subsided.

Tom - Since you fixed the diffuser problem you may not have as bad of an algae problem this year. Your water visibilities will allow filamentous algae to grow if nutrients are adequate in the bottom zones. Since your algae started in June it was probably a cool water form & not a warm water form such as Cladophora. I don't think you have Pithophora in your location. Although both are very similar structure wise.
I don't prefer the chemical treatment method for the floating algae because when you kill it, it sinks to the bottom and decays. This in most ponds recycles the nutrients back into the water column to grow more algae. However in your pond rooted plants may be growing enough at that time to hopefully absorb the recycled nutrients.

I prefer physical removal of floating algae which removes both the growth and absorbed nutrients from the system, minimizing further growth. Since you are not trying to grow phytoplankton reducing the nutrient load in the pond promotes clear water. Nutrients are what are making all the plants including fila. algae grow.

Tom, I don't have thermometers listed in the catalog, but I have plenty on hand...do you want to be able to read bottom temperatures? Did the Trout die, or do you just not see them?

I agree that physical removal of the surface algae mats is the best approach...it's just that not everyone is up for it. How extensive are your algae mats? Last I knew, you didn't have any. As long as you're only treating a small portion of the pond I think that with the kind of water outflow that you have, the release of nutrients from the decaying algae will not be very significant.

Mike, I would like to take temperature readings to track the thermoclines, track spawning temps etc. as the plants develop and the pond matures, so I want to have accurate readings at different depths. I'll give you a call in the next couple of weeks. I'm assuming the trout died as they have disappeared. I never saw any on the surface. Caught a few in the early spring fishing. If you recall last year you gave me a small amount of fish food which I fed sporatically to take an informal fish count. Never saw any after springtime. If you recall we took oxygen readings at the dock and below about six feet there was 0 oxygen with the water temp at 55 degrees. It could be that the thermoclines developed last year in such a way as the trout couldn't survive because the bottom temperature certainly remained cold enough for them through the summer. Maybe as the plant life develops the oxygen contain in the water will change in such a manner as to support a population.

Tom, you're right about the plants helping with the oxygen below the thermocline. If a small amount of sunlight can penetrate to the bottom, beneficial weeds will establish themselves and give off oxygen in the hypolimnion.

Option 2 for establishing oxygen below the thermocline is more drastic. I am working on a small scale "hypolimnetic aeration system." If plants don't establish oxygen down there this year, we could test this system out on your pond if you'd like. We'll talk about it when you call, and in the meantime, I'll get some prices together for different temperature & oxygen meters. I did have a used meter for sale, but I ran my $900 meter over with a truck, so I'm currently using the spare.

A local Sunday morning agricultural program host has been touting whole ground corn meal as the best thing to control algae. (San Antonio area). It takes the potassium away that the algae needs to grow. Recommened application is 400# per acre, but not all at once to guard against oxygen depletion. Very available at all feed stores.