NO offense here either but I tend to agree with Kelly. If you are going to run under the title of lakedoctor (which implies you are a true profesional) you shouldn't expense weed treatment advice casually and sound like a bar tender giving advice to a patron. Most of these herbicides are when in the jug "strong chemicals" and should not be treated lightly or casually. Casual handling and lack of respect and NOT closely following label instructions and application directions are ways how many persons produce poor results with use of these chemicals. Improper use is common with many casual users of herbicides which is why EPA is restricting their use and requiring an applicator license for use for more & more of the herbicides/persticides. Too much misuse.
Duckweed and water-meal are common weed problems as you say, but they are also environmental indicators of highly eutrophic conditions within the pond. When you have abundant duck weed, your pond is telling you, no it is screaming, that it is very fertile or over fertile and a fish kill is VERY likely due to the over enriched conditions. If you have frequent duck weed problems the pond owner should be very concerned with the conditions that causing it to grow very abundantly. The owners should be investigating, exploring and or doing management practices to reduce the conditions that are causing the duckweed problem. If those causative agents are not addressed the pond will continue in it's rapid downward spiral (pond succession). RIF one can reduce the causative agents, it will slow the aging process of the pond and maybe reduce or eliminate the duckweed problem plus reduce the chance for a fish kill. Often due to pond design or location, it is not feasable to reduce the causes of duckweed. Then one has to deal best they can with an aged pond.
