Pond Boss Forums GENERAL QUESTIONS Muddy water Alum or Gypsum

my pond is 7 months old and is still muddy. I was thinking about trying alum or gypsum to solve this problem. The pond is approx. 1/2 acre and is 7.5' deep at the deep end and 3' at the shallow end, so I guess an average depth would be 5'. How much alum or gypsum would I need and where do you get it? What would be the best to use?

Here is a link to help you.I think that alum will change the pH of the water if your alkalinity is low. So if you already have fish, gypsum may be the way to go. Do a search of alum and gypsum on here. That should help you decide. Good luck.

http://wildlife.tamu.edu/publications/taexponds/0905a.pdf

Read this and note in particular the quoted part below. So find out your alkalinity first.

http://srac.tamu.edu/tmppdfs/13452410-46...a25e1fc69a57d1b

Although not nearly as effective as alum, gypsum also can be used to control turbidity but without the loss of alkalinity. Gypsum must be added to achieve a concentration of 100 to 300 mg/L for effective turbidity control. For most ponds, gypsum application rates will range from about 1,000 to 2,000 pounds per acre (Fig. 4). In hard-water ponds (calcium hardness greater than 50 mg/L), the water is nearly saturated with calcium and gypsum may be ineffective. In that situation, alum will be the only effective coagulant.

A couple of years ago, I contacted US Gypsum for their advice and posted the info here but haven't been able to find it.

Look on the web and E-mail them for advice.

Dave is this it ?

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=16;t=000066;p=1

Another alternate to alum is to use one of the polymer versions of aluminum salts. These include poly-aluminum chloride (PAC) or aluminum chlorhydrate (PCH). Both of these are liquids and so are more easily dispersed. The other advantage is that they do not alter pH like alum, but have the same +3 charge, and because they are polymer chains of aluminum, have more charge density. You should be able to buy either from an industrial chemical supplier in most larger cities.
The cost of PAC or PCH will likely be double that of alum on a per lb. of aluminum, but the dosage will be 25% lower and will disperse better so you will see better results. Jar test to see how much you need, but target 10-15 ppm.