How to replace my calendars via iTunes?- not working correctly

iCal has been working great for me unitl a few months ago when I had major duplicating events problems.... I've thought about swictching to something else, but I really do like ical and would like to fix this final problem.....

For the moment, my only issue is that my calendar on my Mac will not sync correctly with my ipad & iphone. These (ipad & iphone) keep duplicating random events for no reason (they are all different, some are all day events, some repeat, etc.). I would like to just replace the calendars on both of these devices with my computer calender via iTunes.... when I use the "replace" funciton it still shows these duplicated events even though they are not showing up on my Mac (are they hidden somehwere?) I have used this replace feature before and its always worked for me until now.

I am not using my iCloud for calendars at all bc I thought that was causing my orginial duplication issues. I have everything turned off (or I think I do) so iCloud will not be a calender issue. I am using my gmail calendar as sort of my online "hub"..... which so far I really do like, I'm just hoping its not causing any of these issues.... I don't think so since I've had issues before I starting using gmail calendar.

Also.... I've moved all my events into one calendar. If I could just figure out how these events are duplicating on iphone & ipad my problem would be solved!

Any advice would be really appreciated!!!!!