How long will alum last in a pond? If their was a windy will it muddy up again? Will it clear back up? Also does anyone have a link on exactly how to do a jar test? I have an 1 acre pond.
Here is some pics of my pond. Its still not quite full yet.
http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=192122&fpart=1

Try this for info - test is at the end,

http://srac.tamu.edu/getfile.cfm?pubid=108

thanks. Is it only a one shot deal or will it prevent muddy water all year round?

It depends on the cause of the problem (what is causing the turbidity).

Im guessing its from water hitting the sides of the pond were there isn't any rocks.

Theoretically, it will last forever.

Realistically, when your pond overflows, you lose alum.

When your have a good concentration of alum or other dissolved minerals, stirred up clay will settle very quickly (minutes to hours). When you have a marginal concentration, it will settle out more slowly (days to weeks). When you have none, and other dissolved minerals are scarce, it will never settle.

If the source of your turbidity is zooplankton, alum won't settle it much if at all.

Well I checked on gypsum and Its only $4.00 for a 50lb bag Il probably go with that. Will it have the same effect?

zoeconner,

Gypsum may work, but normally it takes 4 times the amount of gypsum for the same results seen with alum. Gypsum working in the water is not always a given either.

How much would it take for 100 x 200 14ft pond?

At 6.4 acre feet, I would personally use 500/250 pounds of Alum/Hydrated lime or a ton of gypsum.

Like Rainman wrote , thats the right mixture. Check your PH level before you start and keep checking it as you apply the mix. Mix it in 5 gal pails. We used 3 and put them in small boat with trolling motor. Dumped the pails by the trolling motor and keep driving around and though it to try and spread it all over the pond. Took about 4 or 5 hrs to it done. Pond cleared up in about 3 or 4 days. One thing when I bought the alum it was not powder. It was the size of a BB. We used a drywall mud mixer to mix the pail. Not all the BB's dissovled. So there laying on the bottom. I think when the fish spawn or CC stir up the water , the BB's help keep it clean. Ponds been nice and clear , about 2 ft. or so ever since and that was 7 or 8 years ago. In the spring you can see 5 ft. easy. Then the fish spawn and muck it up some.

Ok I did a jar test for about four days. The water is still cloudy(didnt change a lot) and their isnt a lot on the bottom if any. What do you guys think I should do? Also the PH is good.

what test did you do? Did you see if it would settle on it's own, or did you add a specific amount of alum?

I just waited to see if it settled on its own.

zoeconnor, that would suggest that your pond water needs alum or gypsum to precipitate out the suspended clay particles..du