Many duckweed species have an alternate reproductive method using turions (sinking seeds) that stay in the mud bottom until light penetrates at which time they rise and start the process over. You have to stop the entire process.
I fully expect it will return. I hope that...
1. The hopefully decreased nutrients from removed duckweed
2. Tilapia have spawned so hopefully they can keep up with it.
3. Now i will feel more comfortable with some targeted herbicide applications.
Will keep the problem manageable
