One reason you are finding only per acre rates for this herbicide is that Karmex DF 80 is primarily for agricultural use. It is not legal for home or landscape use. The label I have states "Do not use on home plantings of trees, shrubs, or herbaceous plants, or lawns, walks, driveways, tennis courts or similar areas". There are other preemergents that are more suited to home use.

Also, unlike most post emergent herbicides, preemergents are measured as an amount per surface area, such as per square foot or acre, not as an amount per gallon. You will need to calibrate your spray application to know how much product per gallon you will add to a spray mix.

Here is a link that might be useful: Karmex 80 DF label

does this Karmex herbicide kill duckwed that is in a pond/ How long does it take to tell it is working

Its works great on duckweed
Do a small area first

Unless you know for sure that adding this to other "weed" killers will not make a very toxic substance, think Agent Orange of Viet Nam fame, do not mix them. Many of us still live wioth the legacy of the chemical companies of the 1960's and 1970's that said the dumping their waste on the soil around the plant would do no harm and thes EPA superfunds sites are still being cleaned up and will be for many years to come.

Where could I get Karmex DF herbicide??

I used it 5 years ago into my pond and it did miracles!!!
I tried numerous alternates without any good results.
Karmex is the herbicide I need - but where to find it??

Thanks

Most farm supply stores carry