Eel Grass, Tape Grass and Wild Celery are three different names for the same plant. It has proven to be a very difficult plant to control. We have found a product called Harpoon. It is not labeled for control of Eel Grass, but appears to work well and does a better job than anything else we have tried.
The Harpoon is only available by phone. Please call 1-800-328-9350 to order. A 2.5 gallon jug will cover roughly 5,000 square feet twice for $169. It is best to apply half a gallon with 2.5 gallons of water and about 3 - 4 ounces of a surfactant Cygnet Plus and then repeat the application one week later to cover 2,000 square feet or 50'X40'.