Same. I do not use check valves, though, for the simple reason that my separator and 2L bottle both have lids on them.... If a siphon is created, how much water is realistically going to leave the tank? 2/5ths of not much, by my calculations... Probably just enough to fill one or both of the bottles, then the siphon will cease.I have my 24 oz separator bottle and my 3 liter yeast/sugar/water mix below my aquarium.