My containers are only round concrete usual, I will get a photo .. Only it looks the same , as all ,, It is much lighter than most , I am testing doing a few smaller (possible stepping stones)
I believe this has to do with filamentous algae . (using green water ) I always wondered where those waste algae tanks were going) It turns the starch paste in old paper waste , as it bonds with the Silica in gray cements (Portland) Anyway , the algae filaments become some kind of lime or carbon fiber in the process ,
Here are a couple upside down in the molds
In the Butterfly garden if a plant is not chewed up I feel like a failure
