I've been playing with these fill lines and am having the best luck with the: hmmm... from the bottom up with it upside down, there are two line on the outside you can feel with your finger nail.. one up from there, there's another line that you can't feel and that's where I've been filling it to. It is below the bottom of the tabs so maybe I'm not filling enough now but its working great. Haven't had another leak.
Here is a tip that I read somewhere and that I always follow. After fitting the new refilled tank, take a couple of puffs before putting it in your bag or pocket. That helps to create a vacuum in the system and prevent any leaking.
Hope that helps, however my eRoll hasn't ever leaked, so I can't say for sure that it is a useful tip! Anyway one more thing to try
Good luck
Thank you both! I am going to try both of your tips. I have been so crazy busy lately that I haven't been using my eRolls much the last few days (no time to prep my backup tanks, charge everything up, etc in the evening). That should change after today.
I *really* appreciate all of the help and suggestions in this thread, and it gives me renewed faith in the eRoll. If you all have yours working well I can too.