I've read through this thread. Here are a few on my opinions.
1. Excess nutrients are feeding your FA problem. Excess nutrients can come from many sources. I think in your case they mainly come from: 1. the newly exposed dirt from pond construction, 2. water runoff from hill sides, 3. leaves (decomposition) from the trees along one shore, and 4. a MAJORITY probably come from the stream that drains the neighborhood 15 houses and lord knows what else. Nutrients ARE the problem and FA is a sign nutrients are present in pretty high amounts (as Chad says) . FA will thrive on a nutrient balance (or nitrogen : phosphorus ratio) that will not or cannot produce a green water bloom due to the balance/ratio or sometimes because as mentioned in the posts (Walt) the FA starts first and just out competes the phytoplankton (bloom). First come, first served, sort of thing. ANOTHER hindrance to the development of a bloom can be incorrect alkalinity. (pH is not alkalinity). Basically alkalinity is testing a different substance than pH and Alk is tested a different way. Sometimes liming in itself (increasing alkalinity) will stimulate a bloom IF enough nutrients and the correct balances/ratios are present. Almost always to get blooms excess nutrients are added and it is hoped the application results in the correct nutrient ratio. Rarely does anyone (except academic types) actually test for the nutrient balance/ratios. Bottom line if you lime and fertilize - AERATE to keep things as good as possible.
2. A pond such as yours is predestined to fish kills due to in a valley, lack of wind action, lots of seasonal leaf inputs, lots of cycling of growing, dead or dying FA, and lots of nutrient inputs.
3. Cutrine is copper sulfate that has been chemically modified basically to persist longer in the water column. It involves buffering the copper ions so they more slowly form a copper precipitate. Contrary to what was mentioned, all of it does eventually (sooner or later) become mineralized or bound as copper carbonate and goes into the sediments where it, usually as a inert substance, accumulates as more is added over and over in future treatments. Some copper may be bound in the longer term of the organic biomass where it takes time to work itself into the sediments.
4. Speculation occurred as to what would happen to FA when you aerate. My experience is FA very often reoccurs at some point after ponds are aerated and this is due to excess nutrients still being present that are not used by some other plant be it phytoplankton, rooted vegetation, attached algae (periphyton) or FA. When nutrients are present and other plants are not growing, FA always does grow. Almost never does aeration forever eliminate FA. Sometimes aeration does not even reduce it. Success with this is usually dependant on the source of the nutrients. Good aeration can reduce internal recycling of nutrients and it doesn't do much of anything to dissolved nutrients entering the pond from external sources.
5. As mentioned if you fertilize, first make sure alkalinity is at least 50 ppm (mg/L) (higher is better), apply early before FA starts or establishes, and then reapply enough fertilizer about weekly(?) monthly to maintain enough nutrients present to keep water visibility at about 18"-24". Usually it takes less fertilizer to maintain the bloom than to get it started. Reduce fertilizing in late summer. Mid to Late summer fertilizing can lead to nuisance bluegreen algae blooms.
6. MAYBE - Adding tilapia, and their eating of the algae, and if alkalinity is above 50, and with aeration you could get a natural phytoplankton bloom due to tilapia eating algae and recycling the nutrients in presence of higher alkalinities. This assumes the tilapia will eat your specific type of FA.
7. You mentioned a long tube aerator that would run the length of the pond. Those can be effective. However they provide a gentle laminar upwelling flow and I think they do not provide a strong upwelling to move lots of water forcefully to rapidly turn over a pond's water column which is most beneficial for most pond applications.
Last edited by Bill Cody; 02/07/10 07:18 PM.
