my personal recommendations are:
wet/dry environment such as sump or biotower situations, either bioballz cubesor other shaped things designed to let water pass over every bit of them at any angle there set in
enclosed pressurized or low oxygen envirobnment, ceramic noodles etc. i believ thees do well as you can fit many and they are small
wet/dry environment such as sump or biotower situations, either bioballz cubesor other shaped things designed to let water pass over every bit of them at any angle there set in
enclosed pressurized or low oxygen envirobnment, ceramic noodles etc. i believ thees do well as you can fit many and they are small