Rockfish,
Welcome aboard.
I have used something similar just recently. I used a 3" PVC pipe about 5' long, put it inside a 5 gallon bucket, poured cement, after a week or so, I took gallon jugs & cut off the top 1/4 portion, took 2 wood screws and screwed the bootom of the jug onto the PVC pipe. After that I cut hole with a pair snips all over the jug to allow for water movement. I went to the pond and dropped it in 6' of water.
If you do this, make sure to drop it in the water slow or maybe drill 2 holes in the top so you can attach a rope and lower it into the water. If not, the force of dropping it may remove a jug or 2, or 3.......speaking from experience.
Coupe
