Being new to the group I wanted to take a minute and Thank You for this great informative resource and also introduce myself. I live on a small island in Wisconsin on Lake Superior and have over the past five or so years built a couple of small ponds 150'X75' and a circular 75'. Both are bowl shaped with a max depth of around 15'. We are both blessed and cursed by having predominately red clay soil which is very dense and has great water holding capabilities but other than that is pretty much useless. Both ponds are surface fed with the occasional supplement of well water. I have been patiently waiting for the water to clear up on it's own but have decided after 3+ years to give alum a try. I ordered 200lbs of alum and 50 lbs of hydrated lime which should be here in a couple of days (FYI $40 per 50lbs alum). I think I have a pretty good handle on the application itself but am not sure if I should leave my surface aerator running for better mixing or leave it off for better settling (I apologize if this has been answered elsewhere but I couldn't find anything). I also have a few fish in each pond but not huge numbers BG, perch, BRTR, crappie, FHM and some suckers. Could the suckers be contributing to my muddy water? are they as bad as bullheads or carp? I put a couple dozen in each thinking they would help keep it clean. I thank you in advance for any input and will try and upload some pictures. I'll let you know how it goes.
You will want your aeration off during, and 36 hours after the alum application to allow the floc to form and settle out of the water column. An extra few days to allow the floc to compress a bit on the bottom will be even better.
You should also add another 50 pounds of Hydrated Lime. To counter the acidifying effect of the Alum, it requires 50% by weight of the hydrated lime. Do NOT mix the alum and lime in the same container at the same time as the combination will thicken quickly and be unsprayable.
Here is a thread I started a few years ago that has all kinds of technical information and ideas for various ways to apply the Alum slurry.
Great tip and probably saved my butt. I was going to mix the two together but at a lower concentration of lime. My ph is 7.35, alk 175-200, Cal hardness 90- 120. Which one should I add first alum or lime. I'm thinking alum and then smaller doses of lime to adjust ph.
I add the Alum first as it lowers pH slower. Hydrated lime will raise pH almost instantly.
Are you spraying from the bank? If so, spray your alum and cover the center parts of where alum was sprayed with the lime. Lime is rapidly, and readily dissolved. the Alum never truly dissolves, hence it's being called a slurry.
If spraying from a boat, spray the alum while hand spreading the lime dry, or into the prop wash....again. the lime will spread thoughout the water column naturally, where the alum falls though the water column from where applied.
Also, bare in mind you need more alum/lime over deeper areas to evenly cover water volume, not surface area.
Zach, with all that exposed clay surrounding your pond, and alum treatment may be a waste of effort and money. The first rain event could leave you loaded with suspended clay all over again.
Have you done a "Jar" test to see if the clay settles out yet? Do you have much wind/wave action or bottom feeding fish that could keep your water muddied up?
Even if the water does not settle out, I would highly suggest you plant grass around the pond, or if the area on the right of your pond in the picture is a driving area, I would suggest covering it with a limestone gravel to both filter the clay, and to offset the negative charge in the clay with the positively charged limestone.
