I've tried some of the cart mods for my joye 510 and used the blue foam, regular standard filler and some other foam. every cartridge works okay but then ends up with the foam indented and doesnt work anymore. is that because they have run out of liquid? they seem to run out very very quickly. each cartridge suppose to last a pack they say. Even some of the truer statements say like 6 cigs. I'm getting maybe 3 cigs. its killing me carrying around 5 carts and having to refill them halfway through the day.