Maybe, if it’s not about a bottle of water where we don’t want anything to flow out, one could use some sort of Transparent Material At The End Of A Gel Pen Ref

Maybe, if it’s not about a bottle of water where we don’t want anything to flow out, one could use some sort of Transparent Material At The End Of A Gel Pen Refill to close the plastic pipe and prevent exposure to air to prevent evaporation!