Just a warning stick with granular gypsum and only apply it if it appears visually white.

I bought some pellitized gypsum instead of the granular and broadcast it from a boat. I then noticed that my water was brown. I called up the company and the binder they use to make it dissolved quickly in water has a brown color. They are called Lignosulfates and are made by treating the wood by product ligin with sulfur compounds.

It looked brown in the bag but I thought it was just because it was made into pellets. Live and learn.

Needless to say I am not happy. I am posting to prevent you from suffering from the same problem.

Anyone know how long the lignosulfate take to break down. Anything I can do at this point?

Thanks for the warning Brian, hope someone responds to help.

Hi Brian I did the same thing except I used a 4 inch piece of pvc and filled it with the pellets and then shot water from the well through it and out a nozzle from the shore. I also had placed a mason jar of pond water and a mason jar of pond water and a little of the gypsum mixed in it. They have both sat for 2 weeks now and the clarity is still better in the strait pond water over the mixed! Will keep you posted on the results of my test. I couldn't find anything other than the pellets here in North Alabama. Oh well as you say live and learn.

Bob

Chlorine pool shock will destroy lignosulfates. I did a test in a glass of water. Works at very low concentrations (less than .1 ppm) as long as you don't have a heavy load of lignosulfates.

Hi Brian I have a quick question. Will adding Chlorine pool shock to destroy lignosulfates that were added when I used gypsum pellets to clear the suspended clay in my small pond have any effect on my fish?
Web

Here's the best I can do on my lunch break:

If you put more than .1 ppm it will probably kill your fish. It will already cause stress at that level. At higher levels it will kill the fish. Plus, check the law.

Adding white powder gypsum will help too.