Cider has a pelicle film on top even after campden tablet addition

[jceg316]

I made 4.5 litres of cider 2 weeks ago and added 1 campden tablet. The aim was to kill everything but saccharomyces which can survive sulphate (according to Craft Cider Making by Andrew Lea). A couple of days ago I noticed a film develop on top so I added another campden tablet, but the film has developed more. Is this beyond repair or is there anything I can do to save this cider?

Thanks in advance

 

[DavieC]

Did you add yeast? If so are you sure its not fermentation krausen?

 

[DavieC]

Ps..have you taken a gravity reading?

 

[jceg316]

I'm sure it's a pelicle and not regular krausen. I've just added yeast now to see if it outcompetes whatever wild yeast/bacteria might be in there.