Summers where I live typically have 80F nights and it can easily pick up to 95 degrees during the day.

I have a plastic trash can (which I bought for this purpose) that I have filled up with water. Currently, my apartment measures 79F, but measuring the water in the trashcan gives me 70F. 

Can I just place my fermentation tank in this tub of water to counter the heat?

Will this method work during the summer, when I have a 90-95F day?

Will bacteria that collects in the bucket of water be a greater threat to my vodka-filled airlock than the bacteria that collects in my closet, where my fermentation tank is currently stored?

Thank you!