Thanks Bill, great post!
One thing that I didn't elaborate on is the food. jpsdad, here is some info that I didn't post, that leads me to believe that the reduction in FA that I saw the first year of switching food brand wasn't coincidental.
A PB member here did a feed test in which he had (roughly) the same number of fish in a cage, of the same size and weight. IIRC 3 different cages with identical "standing crop" loads. 3 different feeds. He monitored the fish and the food that was fed to the fish. He was specifically looking for how much food to feed to achieve the same weight increase in the fish. His results were (again IIRC) 40# of Optimal BG or BG Junior feed, 60# Purina Aquamax 500 or 120# of Sportsman's Choice from TSC. all put the same amount of weight on the same amount of fish. I switched from Purina to Optimal and saw the difference. Was it coincidental? Maybe, but then again maybe not.
I was able to reduce the amount of feed going into the pond by 33% and still have the same fish growth. I have observed the same lower level of FA growing in the pond ever since switching food brands. So in essence I reduced the amount of nutrients going into the pond. That might be coincidental, but I don't think so since the FA has been less ever since switching food, and that has been 1 year before Optimal hit the retail market. Would I have reduced the amount of FA in the pond if I had stopped feeding completely? Probably. My pond is also a groundwater pond, so there is water flushing in and out of the pond through the bottom of the pond. Can I prove that? No. But anecdotal evidence shows that this is happening. Sand bottom, same as other ponds in the area, and some of those ponds are designed NOT to receive surface runoff and those ponds will rise and fall more than they should from only rainfall. How much water is exchanged? Not sure, but my pond, at approximately 1.1 to 1.2 surface acres will drop between 36"-50" every year before winter, and this year it is down 69", and is approximately 0.44 surface acres now.
Now reduction in nutrients will help greatly, but you have to reduce the nutrients and especially the P in the pond by a considerable amount to show a difference in the crop of FA that is grown. You can also reduce the P in the pond by raking out all the FA that is growing and get it out of the watershed for the pond. It's not enough to rake it out of the pond and leave it on the ground next to the pond.
