What you need is a test tube brush or the like and some dish soap or other mild cleaner. Send some hot soapy water through the hose and then use a long piece of wire attached to the soaped up brush to pull it through the line. Repeat as necessary. Same thing works with canister filter hoses too, just make sure you rinse it very well to get all the soap out. I might add there are a number of ways to get these hoses clean and they all work pretty well, but this is how I do it.