Who Gives A Fish Forums

I found the answer - the Fluval A20198 is the part number for the 407 canister, and it looks like the 406 and 407 parts aren't compatible.

To address the issue with your duckweed and other plants dying out, let's break it down. Plants require light, CO2, and nutrients to thrive. Given that duckweed is a surface plant, it's likely that light and CO2 aren't the culprits. This leaves us with nutrients as the probable cause.

Duckweed ...