Hello everyone. Worried that I am going to have a fish kill. I have a 1.5 acre pond that is approximately 5' deep located in south Louisiana. Before I added agricultural lime to the pond the water alkalinity was 20 ppm and a 6.5 ph. I added approximately 3 tons of lime to 2/3 of the pond. This was done a month ago. The water clarity started to change from very clear to green. Over the last several weeks the green color in the water intensified. Today I noticed a blue green algae against the down wind bank. Where the algae is piled up it is almost white in color. I have not added any fertilizer. There is a lot of flow through the pond when it rains. Last significant rain was a week ago (approx .5"). Over the last couple of years the pond has been very clear, which lead to a lot of weed issues. I wonder if increasing the alkalinity allowed the water to absorb nutrients that were locked up due to low alkalinity. what can be done to correct my situation?
That's exactly what happened, once the alkalinity rose, it allowed the nutrients that were in the pond to become available to the algae. I would do a nutrient reduction application of alum/hydrated lime, or do a treatment with Phoslock. You could find a Helena chemical supplier in your area and ask them what they have to remove Phosphorous from pond water. They have a product that is similar to Phoslock too.
What is you water clarity? White stuff may be protoplasm from dead plankton (which is normal but not visible except with strong plankton bloom). Sometimes it looks like a light white mist covering the pond and will accumulate on the wind-blown shore. Did you have a soil test done? That would tell you what may be in store.