In hot climates like UAE, the fluid will evaporate through the hole faster than consumption. I suggested putting a balloon over the hole to deal with expansion but it's a little more complicated as you would want a way to let air in when you use the sprayer. Prob just putting the balloon on when it's 70f at night would be enough.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)