refill water in my bubbler airlock to fill line?

Finished brewing my second batch of beer last night and am using an ice bath method to keep my temps down as my appt is about 75 degrees. I know from reading other post on here that a sudden drop in temp of your fermenting vessel can cause the liquid in your bubbler to be sucked inside. I was using clean water so hopefully thats not an issue, but should I refill the bubbler to the fill line or will it be fine as is. I'm at work now and noticed it on my way out while changing the ice so its been bothering me all evening. Will not having enough water in the bubbler mess with the fermentation?

fill it up to the fill line with cheap vodka. that will kill any bugs that may land on your airlock, and if it gets sucked in no worries...wont contain any mold or bacteria and will just give you an abv boost.

^^ He nailed it.

On my first and only batch (so far) of apfelwein I pitched the yeast onto the appeljuice that had been in my car for about 10 minutes. This was in july so I am sure the juice was at least 10-15 degrees warmer than my basement. As the 5 gallons cooled over the next day or so it sucked back 3 airlocks worth of sanatized water/honey bourbon haha

Yes vodka and no worries. I'm about to crash cool and anticipate suck back (zing) so got my vodka on hand to refill when this happens.

Alright thats what I'll do. Thanks for the advice everyone