I've had a few people say this is not possible also, but I cannot think of any other reason other than cross contamination. The timing of it was so spot on and water Paramus show nothing. Anyway cipro treatment day 3 . Nems looking much better and has not deflated for 2 days. On day 1 I was really worried. I woke up to find my nem had virtually turned inside out , I have never seen anything like it , but I stuck with the programme , siphoned everything off, changed the water 100% and re-dosed cipro. Today it's looking more like its old self , but not going to shout about it too much, I'll feel better when it's back in the tank. Again thanks for all the help and advice everyone