Paphos Life

Whilst emptying the pool skimmers I have noticed that the hose at the bottom, which takes the water back to the pool pump, is blistering...
Is it likely they will fail? If so is it a difficult job to replace?
They are about an inch and a half diameter at the skimmer end but considerably bigger to the pump...So is it a pipe within a pipe system?.
Thanks for any info.....

Is it chlorine crystals that a building up around the entrance to the pipe not the pipe itself ,? this is quite common I have been told. Lefkes.