AquaNeatAqua Neat is sold in 2. 5 gallon containers. Aqua Neat is used in lake and ponds to control aquatic weeds and nuisance aquatic herbaceous plants. It works best when used in conjunction with a surfactant such as Cygnet Plus. Aqua Neat Herbicide is used to control cattails, brush, and weeds that grow out of the water. To use spray onto the foliage of the plant and it kills the plant and roots. Effectiveness may be reduced if rain occurs within six hours