Back carbonating with sugar

[Supersocks]

For my first couple of brews of turbo cider i added some demerara sugar into the bottles before bottling and they fizzed up nicely after a few weeks.
The next few brews I used white sugar as Tesco was out of demerara when i was getting supplies and they barely fizzed at all, even after a month so I ended up fizzing with a Drinkmate fizzer.

So i guess my questions to more experienced brewers, does the sugar type matter and if not and is it possible i let the last few brews go too far before bottling and the yeast was dead?
For my latest brew, just bottled yesterday, I've used demerara again so time will answer the type question i suppose but it would be good to know for sure.

 

[user 44889]

When i bottle my Cider i add carbonation drops to the bottles... just look like a sugar cube. So easy and no mess. I only use 250ml bottles so 1 per bottle. If using 330ml or 500ml add 2. Does a nice job without going mad.