I have a 1/3-1/4 acre pond, I think...i'll attach a photo of it. Well, I used 200lbs alum and 100lbs hydrated lime(bought both from rainman). I sprayed the pond in 4 quadrants and it cleared it up to 2 feet maybe. It wasn't bathwater clear at the edges like in some of your photos. well the next afternoon...almost 24 hrs later, I had family over to the place and kids were swimming. Well, the pond is back to what it was before with no change after about 3 weeks since I did the treatment.

Can I put enough alum and hydrated lime in my pond so that even when it is stirred up by swimming, or the dog, etc. that it goes back to being good visibility again like before the swimming, etc.? I don't mind treating the pond once a year or even twice a year but I'm not going to treat it after every swim.

Thoughts? comments?

Might look into putting in a pile of gypsum rock as a longer term solution.

Clay molecules bind with alum and sink as they become heavier than water. Stirring up the bottom could cause them to suspend again temporarily, but you aren't breaking the bond between the alum and clay molecules so they should sink again. I suspect your initial treatment might have been too light, but I'm not an expert by any means. Rex should be able to direct you.

I don't know what it is about my ponds, but you can stir up the nearly pure clay bottoms and it settles in a few hours. Never used alum. Any explanations?

Gypsum, at best, only works in clearing suspended colloidal clay about 30% of the time. Water chemistry has to be nearly ideal for the addition of gypsum to be effective in clearing....Often, the large amounts of gypsum needed to have any impact on clarity also make it considerably more expensive than Alum....then gypsum has to be as evenly spread as possible....With Alum, there is no guessing if it will clear colloidal clay, and what is cleared out of the water column, is permanently cleared.....Stirring up unbound colloidal clay, unbound to the Alum, is the saame effect as new colloidal clay washing into a pond during a rain event.

Justified, my guess, since I've not seen your pond, is it is closer to your 1/3 acre size, with a deeper average depth. 200 pounds applied pretty evenly/proportionally will clear one acre foot of water, and stirred sediments will normally settle in seconds to a few minutes (if water is left undisturbed again). Kids swimming could cloud up a small pond and keep it stirred for a while, but with the proper "dose" of alum, it would have cleared within minutes of the kids getting out.

would it be best for my kids to get in, stir up the water like crazy, then apply the alum/lime so it bounds to all the collodial clay?

I'm wondering if I spray it all over the pond, it bounds to the stuff in the water, but not the stuff under the initial layer of clay on the bottom of the pond then non bounded stuff will just be stirred up again.

I'm not sure either, but sounds awesome.

Easy explanation is your clay is not "colloidal"...(extremely fine and microscopic particles, all negatively charged). Most clay does not separate into microscopic sizes, and/or those non-colloidal clays are often attached to other, positively charged molecules that create tight bonds.

Actually, that (kids stirring up things as much as possible) would be a heck of a good idea!

The NRCS agent talked about clay and muddy water when designing my pond. He said some clays were a problem and others were not. That is when he suggested if I wanted clear water to line the pond with a thin layer of topsoil as the silt and sand particles in topsoil are much larger and would not cause turbidity problems. He was correct in that assessment in that my main pind I did line with topsoil and my other ponds did not and there was definitely a difference.

What he did not tell me and I later learned here on PBF is that the topsoil is loaded with nutrients that can lead to excessive nutrient load and algae problems, which I have had.

But the point he made is not all clays are equal in creating turbidity.