Mike,
We used it for a period of 2 months in preparation for wfp. It did break down the film which made the transition less traumatic as there were hardly any spots.
Sarah
Ah, Sarah, that could be that because when you first start with WFP, if you're a concientious window cleaner (which you and 'hubby' are; I guess); you put a lot of effort in. Scrubbed frames, windows and rinsed well.
Unless you left one area out and just cleaned them with normal tap water; as a 'control'; you don't really know if it 'breaks down the film'; if indeed there is a film!
Prior and leading upto using a WFP, we used Fairy and tap water, and didn't clean the frames.
We changed over to WFP without any problems.
I'm only pointing this out, because I've read a lot of stuff here over the years about how to prepare your work for WFP.
Looking back, I think some of it just creates extra work at no real benifit.
Regards,
Tosh.