I agree, Keith. My duckweed wading pool was originally filled with FT water, but now just gets replenished with rain water. A couple times a week, I dose it with urine. It also gets fertilized with leaves that blow in and the occasional over-ripe papaya that falls into it from the tree above. I use no aeration or circulation or other fertilizer whatsoever. I may have said before, I harvest about 1/3 of the duckweed twice a week and it stays replenished at that usage level. My duckweed pond is in full sun until about 3pm. I've seen reports that duckweed can double in 24 hours, but that may be way too optimistic for practical application. Based on my own system, doubling takes about 9 days.Originally Posted by keith_r