If my math is correct you should mix 12.8 ounces of product with one gallon of water for spot spraying.

This sound right? Or is there a better ratio.

Thanks!

Depends on the target - planktonic algae is lower, filamentous higher, chara higher still. What are you treating?

Treating FA

Thanks

From website:

To apply Cutrine-Plus Liquid, determine the volume of water to be treated in acre-ft. For Filamentous and Planktonic Algae, use 1 gallon of Cutrine-Plus Liquid per 1.5 acre-ft of treated water. For Chara, use 2 gallons of Cutrine-Plus Liquid per 1.5 acre-ft. of treated water. Dilute with a minimum of 9 parts water. Spray uniformly over the water surface as a rain of coarse droplets. Contact with Filamentous Algae will be improved by breaking apart heavy surface mats before application.
For Hydrilla, use 2 gallons of Harvester Liquid mixed with 3 gallons of Cutrine-Plus Liquid per 1 acre to be treated. Dilute mixture with a minimum of 9 parts water and apply as a surface spray or by underwater injection. Add Cygnet-Plus Liquid to increase penetration and contact.
Treat heavy infestations in sections of 1/3 to 1/2 of total algae volume to avoid oxygen depletion. Allow 5 to 7 days before continuing to an untreated section.

Like in TJs post I think adding a surfactant will also help. Are you just treating the floating stuff?

When I spot spray my FA I use one part Cutrine Plus liquid to 9 parts of water. I generally use cheap "pink" dishwashing detergent as a surfactant. Although I have never seen anyone else recommend the following, I also add blue pond dye so that I can better see where I have sprayed. I probably add a cup of dye to four gallons of water.

I am not sure acre feet of water are that important in spot spraying the surface algae.

I don't think soap is good for your fish.

Thanks! 9:1 is what I read on the label and how I came up with 12.8 ounces per.

I have a 16 gallon sprayer and mix 1/2 gallon Cutrine Plus when I fill it up. It sprays about half way around my pond and always works fine. On a hot sunny day the FA around the bank where I started spraying is already turning brown by the time I use it all.

Ok then. Spot sprayed with 4oz to a gallon today. I'll report back in a few.

Thanks everyone for the replies.

Good luck. Should work well on surface mat spot spraying. It doesn't make much difference how strong you mix it because the water is just a carrier for the active ingredient. IOW, a heavy spray of a weak mixture will work the same as a light spray of a heavier mix. My problem with mixing it too heavy is that I tend to use too much and run out of spray before I cover the intended area. By mixing it lighter I can cover the area and then turn around and respray heavy areas if I have some left. But that is just me and my ineptness showing.