I'm planning on using marinepure blocks in my refugium instead of sand and rubble as they are more porous and also its easier to clean than sand and rubble. I want to tumble my chaeto with either an airpump or a submersible pump with a spray bar. I'm not sure if the copepods will be able to thrive in a refugium with moderate flow, a ball of chaeto constantly tumbing and instead of sand and rubble only marinepure blocks. If not can someone please tell me what to do...