We have been made aware of an issue with the mold on the return nozzle attachment. This issue effects a small batch of CUBE 10 and CUBE 20 aquariums. Our manufacture has since corrected the mold for the nozzles and re-produced the nozzle.
Replacement nozzles are available for those who have received one with an issue. Please email Customer Support at email@example.com with information regarding your nozzle issue, proof of purchase and mailing address to send the replacement out.
In the meantime, please firmly (but gently) press the return line into the connector and use Teflon tape to secure the seal until your replacement arrives.