Pond Boss Forums GENERAL QUESTIONS Help Small pond high inflow from large watershed

I tried fertilizing to keep a decent bloom, but every rain event seems to wash out my fertility and cause a crash. I am scrapping the fertilization plan. My pond is too dynamic. It will hence forth and forever more support what it can naturally, although I will continue to feed as normal.
My question here to those more experienced at pond management is this.
My last fertilization was from a liquid fert. I over did it a bit, and was actually hoping for some rain to clear it out a bit. Well we got an all day soaker, lots of water flowed in, and lots of water flowed out. Goodbye greenwater hello milky tan water. Almost looks like suspended silt, but it is not, as my entire watershed is grass, and as I said this was an all day soaking rain, not a gully washer. Is this milky tan color the result of planktonic die off? I have no water clarity at this point. A few inches max. I have bottom aeration, and since this crash has taken place, am using two pumps to spray water. Fish are feeding, but not as vigorously, I attribute this mostly to visibility. May be a DO issue as well, but I dont think that is the main factor. I do not have fish piping at the surface in the morning. I guess what I am asking is, is it normal to go from pea soup to silty looking water from a major phytoplankton die off?
To give you guys an idea of what we are looking at here I have a 1/4 acre pond with probably 20 acres of grass watershed. When the pond was dug last year, it only took two rain events to fill it to overflow. That is why I am just going to walk away from the fertilization, my pond is too unstable.
Prior to this past fertilization, I typically had 20 inches of depth clarity. Shortly after the fert. I ended up with only about 10 inches. I was freaking out a bit, and then the rain came, I was relieved, but four days later , my pond has even less clarity, I am afraid I am not out of the woods yet. Anyone out there have any insight? Thanks in advance.

Can you post a pic ? Often as a phytoplankton bloom ages it turns to brown which indicates that zooplankton (brown) is abundant while the phydo (green) is lessening. Keep the sprayer and aeration going for now.

On the fertilization idea is your water control structure designed to flow water from depth rather than the surface ?

unfortunately not, I did not do my homework prior to construction. It is a topwater overflow. In fact I have no choice buy to aerate and destratify the water just to avoid inversions from the high inflow. Learned that the hard way a couple of months ago when I walked out in the morning the second day after a hard cold rain, and every fish in the pond was at the surface gasping for air.

Oh, and more info just for the heck of it, does not really pertain to the question at hand. The pond is stocked with HBG(mistake), Crappie(mistake, though they do have the complete line down their dorsal, so they might be hybrids), Chain pickerel, BG, RES, few Pseeds, couple longears, CC, FHM, GSH, Gambusia, Tilapia. One grass carp. Northern studfish, rosyface shiners, lots of tadpoles from green, bullfrog,leopard, gray treefrog, and I think the eastern toads have all already morphed. It is rather diverse, but not too heavily stocked in any one area. I plan to add another apex predator besides the chain pickerel, and crappie, but have not decided on LMB, or HSB. I also intend to be an apex predator myself, along with my 30 foot seine.

I hope I can give you some hope, but we will see. I have a pond in a similar situation. 3 acres with about 400 acres of runoff going into it, or about double your ratio, with about a 50/50 split of pasture and forest. I really don't think there is any way to control the fertility of the water in this situation unless you monitor and adjust constantly, but then you risk more frequent and possibly larger DO crashes. Fertilizer just washes out with every decent rain event. I believe my pond's marshy area on the upstream side helps with any sediment or upstream contaminants. The vegetation there slows down the water and soaks up a lot of stuff I don't need in the pond. The fish don't seem to mind the fluctuations and there are 14" crappie and 5 lbs LMB in it, plus it has lasted for 115 years now in one form or another.