The first pond has been muddy ever since it was first built. Over the last several years we have tried Alum once or twice and it cleared it up slightly but then would get back down to below 8" of visiblity. Last month we got some gypsum rock and added it to the pond. In less than a month it has started to clear the pond so I'm hopefully it will work in the long run. Here are a few pictures.

Water taken from the surface a few years ago.


Water taken from the bottom of the pond on the same day as the first picture. I can only assume the clear settles out in the cooler water down deep.




Gypsum pile. Heavy equipment makes it alot easier to move.





My helper sitting with me.



Gypsum pile just after it was placed.



Water Clarity as of 6/11. 3-4 weeks after the gypsum rock was added.

How exactly does the gypsum clear your water? Does that work only in ponds of a certain pH or hardness?

I believe it works the same way as alum and changes the charge in the water and allows the suspended clay to settle out. With gypsum you have to use more of it but you don't have to worry about pH swings like you do with Alum.

I don't know if pH or hardness has an effect on it. I took a water sample from my pond and then put a baseball size gypsum rock in it. The sample cleared up in less than two days.