Brooksea:
On the subject of cleaning: We use 6 foot tubes for the Res Med bi-pap, the Respironics Cough Assist, and the Respironics Trilogy. The tubes are inter-changeable. The reason for the length is simply for positioning the equipment appropriately from bed or chair.
We have replacement masks, filters and hoses on a three month replacement schedule. Therefore, I always keep one tube in reserve for each device when I receive the new one. When I remove a hose for cleaning (once a week for each device), I replace it immediately with the previously cleaned alternate so there is never a "wet" hose on the device (potentially extremely damaging to the Cough Assist).
I have never observed gunk in a tube. It is important to clean the tubes and masks with a dishwashing liquid that does not contain an anti-bacterial substance, which can produce an allergic response and all kinds of problems according to the information I have been provided. Ivory or Joy are the best--I use Joy. I clean masks and tubes in a dishpan reserved only for the device attachments and no other use in order to prevent contamination. After cleaning and rinsing the hoses (completely), I hang them over the shower stall to drain. I use a paper towel to gently clean the masks and then air dry them for several hours before use.
Finally, my husband always allows some air to blow through the devices to remove any possibility of residual moisture before he uses them.
I hope this helps.
V