Hi Rainman, the good news is the pond has only had a slight weed control for Cattail. I got into trouble for saying this before, but I used Defender bought at Walmart for less then $10, mixed 4 oz. to a gallon and it worked great. The pond is very clear because I don't have anything in the pond that would stir up the bottom. It is wonderful to walk around my pond as see pond life as if I was looking into an aquarium and even photograph it.
John, I have to throw this up there to protect my applicators license. Indiana law reads that if I know of an incorrect application of a herbicide (i.e. using a terrestrial chemical on water) and I don't say something about it, I could lose my license.
So, with being said, it is against federal regulations to use any herbicide for any application that is not specifically stated on the label. i.e., if the chemical isn't rated to be used in ponds, then don't use it. For instance, Round-Up is glyphosate based. It is not labeled to use in, or around a pond. ShoreKlear is also glyphosate based and it IS labeled to use in and around ponds. It's not the ghyphosate, it's the other ingredients in it that is the difference.
I looked up Defender in the on-line WalMart store and can not find it. The only Defender herbicide that I could find on the internet is spelled Defendor, and is produced by DOW. The active ingredient is florasulam, and it is a little bit more expensive than what you said you used, at $233 for 32 ounces. It too is not rated for use in ponds.
