I have just recently become a member in the fall of 2004 when i visited your trade show in the Du Page County Fairgrounds and although I have not been able to attend any meetings in 2004, I plan on attending whatever I can in 2005.

OK, enough chit chat. Down to business. I have a three year old pond that measures 16' by 11' and is 4' deep at its lowest point. There are a total of 13 koi ranging in size from 8"to 15" in size. I have a skimmer and two bottom drains that go to seperate external pumps (one for each type of filtration, respectively). The water in the skimmer runs through a screen and a series of four- 2" thick filter pads, and a leaf basket before it hits the pump. The two 3" bottom drains are gravity fed to a plastic 55 gallon drum where the water goes through a screen and three filter pads, into another 3" outlet, through a leafbasket and then to the second external pump.

Both pump #1 and #2 push the water to the bottom of a second 55 gallon drum which is filled with bioballs and another 2 layers of 2" thick biofilter material. The water then exits the top of the barrel through an opening and cascades to a "minipond" and then cascades again into the main pond. The minipond is 5' by 4' and is 1.5' deep and is lined with 3-4"river rock and full of aquatic plants, submersible, floating, and rooted as well. The main pond has a 1' wide shelf around the edges also with aquatic plants. In the central area of the main pond are a few waterlily plants as well.

The screens in each filter and the leaf baskets act as a physical filtration and the biofilter material, 3-4" river rock, and bioballs act as the biological filtration for the bacteria to thrive on, along with all the aquatic plants in my ponds to help keep the water clean. Oh yea, I also installed a UV light and a separate submersible pump to operate it to rid my pond of the green water problem I have been having.

With all that said, I know it is quite a lot of info., my problem now is with the string algae. The pond is in the backyard and receives sunlight from morning to night since my yard new and there are no established trees and my house creates no shade for it. I physically remove the algae from time to time, but is really becoming a hassle. The UV light is doing its job and keeping the water clear, and the filters keep the water free of dead plant material and fish waste(I clean off the filters twice a week with a hose), so what should I do now?

There is plenty of water movement, a 55 gallon drum full of biomaterial, UV light, aquatic plants, physical filtration, and no "dead water" areas in the pond. The only problem is the sun light. I am not willing to install a shade cover and I have already planted some trees to create shade, but they will not be usefull for a few years yet to come. The pond has no rocks on the bottom except for a clay 1' wide chimney tube for the fish to shelter themselves from the sun as well as any predators that may come along.( None so far, knock on wood). I do not use fertilizers for my plants, there is no runoff entering my pond, I don't overfeed my fish; if anything I underfeed them, due to me living alone and a hectic schedule. The only thing I can think of is to medicate the water with some bio chemicals to break down the string algae. Now here is the long overdue questions.

#1. What is a good brand or type of additive I can add and at what dosage for my size pond?

and #2. If there is something else I am overlooking that can help, please let me know.

I have a tight budget so please do not go overboard with high cost solutions, unless that is the only way. I have tried and believe in the "all natural" approach by using more plant material to absorb excess nutrients, but frankly I have no more room for them and it still does not work. All fish are extremely healthy, as well as the plants, so I don't want to use anything that may put either in danger.

Sorry about the novel I just wrote, but I figure the more info you have, the better you can understand the problem, and the easier it will be to come up with a more defined solution to the problem. Thanks for your time and I hope to hear from you soon.

-Patrick Svacha, Plainfield IL

What a wonderful and well thought out setup. By my calclation, you are running a 5000 gallon pond with excellent mechanical and biofiltration. Remember that everything in your filtration system will serve as a platform for your bacteria, not just the bioballs. Your mat will need to be cleaned periodically, but a few hard whacks on the driveway and a rinse in pond water (dechlorinated!)will do that nicely.

You've already identified the source of your problem and installed the beginnings of the solution. You have lots of nitrates as a gift of your fish and your excellent bioconversion. The string algae uses your abundant sunlight and the nitrate to thrive, and to some degree, is doing you a favor by eliminating the nitrate which can be toxic to fish in high concentrations.

The most cost-effective solution to your problem is shade. The next is mechanical removal (a brush on a stick to remove the large masses in the water). You are already using verge and aquatic plantings.

*Please* do not get sucked into using chemical "remedies". None of them work well, and many are toxic to fish and wildlife.

Barley straw has been shown to be effective, but requires some time and warm water to work, since it is an interaction between substances eluted from the straw and natural bacterial action. It also stains the water a light amber color. A number of companies are producing colorless barley straw extracts, but they are pricey, and I have no evidence of their effectiveness.

You could buy a Plecostomus (armored catfish) and let him graze. You will have to bring him inside for the winter, since the species is tropical. Pleckys love hair algae, and will keep your pond nicely shaved down to a lush "crew-cut" appearance.

Bob Passovoy
President
MPKS