I have a pond that tends to be very turbid in the fall and winter months (2 or 3 inches of visibility). The reading I have done suggests that this level of turbidity renders fertilization useless because you don't get adequate sunlight penetration to have the desired impact on the food chain. I diagnosed the problem as clay turbidity and bottle testing showed that I could clear the pond with gypsum . This spring I attempted to clear the pond by adding 2 tons of powdered gypsum by hand. The pond is approximately 7.5 acre-feet (1.8 acres surface area). The gypsum did not work, at least immediately, however in the past three weeks or so the pond has cleared to approximately 1 ft of visibility. The pond immediately downstream has about 16-18" of visibility and I attribute this to our best water feeds this pond. Our pond overflows to the next one when it rains. Both ponds have similar bottoms, pH, alkalinity, hardness, and the watersheds look practically the same in terms of vegetative cover. I am afraid of alum as I worry about dropping the pH too much. The pond pH is approx 6.8 and alkalinity is only 30-40 ppm.
The pond was stocked with 200 channels - 8 to 11", 200 bass - 8 to 10", and 1000 coppernose bluegill - 3 to 5" last July. There was a preexisiting population of green sunfish of all sizes and a handful of channel cats. In spring, summer and fall I feed with high protein pellets - probably 15 lbs per week. Some of my neighbors feed as well although not as consistently.The bass we stocked were feed trained and they are growing but not as fast as the channel cats. Some of the channels have almost doubled in weight. Visually, I see quite a few small panfish since the water has cleared- 1 to 3" in size. I also put in 25 lbs of 4-6" tilapia about 6 weeks ago to add to the forage base.
My question is this, is 12" of clarity enough to fertilize the pond or do I need to try to get more clarity before fertilizing? I'm a newbie at trying to manage a pond so any and all advice is greatly appreciated. Adding gypsum was fairly expensive, time consuming, and was a lot of work as I simply shoveled gypsum into my trolling motor propwash, one shovel full at a time and I tried to distribute it as evenly as possible. I'll add more gypsum if I need to but hoping not to have to.
Our long term goal is to get a good mix of all sizes of bass, bluegill, and channels and be able to do some harvesting of each. I realize the cats might not breed without addition of the right kind of habitat (I put in 20 or so cinder blocks but I think that won't be enough by itself). We want to get the bass/bluegill populations breeding and self sustaining to some degree. I have every reason to think the bluegill (and greenies) are breeding and providing a reasonable forage base. Not sure if the bass are breeding or not.
