Aeration and Algae
Question: I bought a 24 foot windmill from you in 2010 and installed it midsummer 2011. I have algae on my pond my the time I installed it so it did not take care of the algae this summer. I am wondering if it will take care of algae next summer. My pond is a 1/4 acre and 10′ deep or will I also need to get a fountain?
Answer: Eliminating algae is dependent on several factors. Nutrient runoff is probably the most important. Aeration can help eliminate existing nutrients in the water by adding oxygen and therefore beneficial aerobic bacteria which consume excess organic matter, nitrogen and some phosphorous.  It may take a little time for this to work, espeically if there is more than 2-3″ of organic matter on the bottom.
If your pond continues to get nutrients thru fertilizer runoff (from farmer’s fields, livestock in the water shed, or from another source), then completely eliminating algae can be a challenge as there are always nutrients available. Algae is a plant and needs three things to grow (food, water and sunlight).
A great alternative that we use a lot is to filter the sunlight to keep it off of the bottom, where most algae starts to grow before rising to the surface. We have several pond dyes that can accomplish this. You can also combine aeration with a pond dye for sunlight filtration with some additional beneficial bacteria. All work together to help reduce the amount of algae and vegetation in your pond.
A fountain in a pond 10′ deep would be great for aesthetics, and will add some additional oxygen, but probably won’t stop algae from growing.
For 2012, I would try aeration, some pond dye (keep it in year around – even over winter), and some beneficial bacteria once the water temp. gets back up above 50 degrees. The fountain could be added anytime, but is more for looks than actual algae control unless your pond is 4-6’ deep.  Hope this helps!