Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Please help ID this alge.

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We left about two weeks ago for a trip and returned to this in my pond. I'm pretty sure it has been on the bottom, but has only surfaced in the last two weeks. I believe this to be hydrilla. But not positive. Is there anything besides grass carp to cure this?

Not likely Hydrilla, but your photos are inadequate for ID-purposes.
Take and post a photo of a 6" sprig from the plant in your hand or on a surface with a coin placed next to it; preferably in a larger format than your previous pics.

In addition take a picture of the 6" end piece that was placed in a dish with a little water to the plant lays natural with leaves spread out.

Bill; my strong hunch on the ID is Chara due to the stuff's growth-habit and varied coloration.

Kelly's hunch is probably correct. Lets see what shows up in some close up pictures that show 'leaf' stem structure.

I have had my local extension service ID this as nitella. They recommended copper sulphate or Hydrothal 191 to get rid of it. Has anyone had any experience using either of these? Wondering which one to get. Also, not sure how much to add to my pond. My pond is about 3.5 acres at full pool and would average 6'-8' depth over the entire pond. Thanks for any comments.

Copper sulfate is a strong fish irritant and hydrothal 191 in liquid form will kill often cause a fish kill as well. The easiet and safest thing for chara is cutrine (chelated copper) and the best for for chara is cutrine granular.

In my experience, application of hydrothol has never resulted in fish kill events. The only instance where I'd see that possible is if an entire pond was treated at once, creating a DO crash. Partial treatment is recommended weeks apart to eliminate this possibility.

See this

http://aquaplant.tamu.edu/plant-identification/alphabetical-index/nitella/

Using 191 and working from deep water to shallow water can trap fish in shallow water, resulting in dead fish. BTDT

I've killed a few fish with Hydrathol granular myself, but they were small, and buried in established coontail as it was being treated. Now, I only use it when an undesired plant first emerges, and I've had no further fish losses. It's definitely a chemical that should be used as directed though.

I treated from shoreline and outward multiple times and no morts thus far.

That's the way it's supposed to be done.