The documentation
http://www.alphacool.com/download... states the following:
"Connections
All connections are based on the classic G1/4 inch thread, the standard thread in water
in the field of water cooling. Therefore, all connections can be exchanged for others at any time if desired.
if desired. This also means that you can use thicker hoses or even hardtubes at a later stage to
hardtubes to make your system more individual."
But I have not replaced any tubes myself.