Join Date: Jul 2011
Location: Fort Myers, Floriduh
After a bit more experimentation involving most of my tanks, I have realized that there is a fine line between having enough duckweed and having too much. In two of my tanks my duckweed ran out of control and caused a bit of crypt melt as well as holes in the leaves of my anubias and java ferns. In my other tanks I have either severely thinned the duckweed or removed it altogether. The duckweed does help remove algae, but it also, as noted in the conversation above, diffuses light to my crypts. Apparently too much duckweed cover depletes all of the available nutrients as well as blocking/diffusing the light, and if I let this get out of control then it can and will harm my plants. Unfortunately, this stuff grows so fast that it almost needs to be removed daily.
I even have duckweed in my water bong!