Not terribly, rough fit (like, my tub has a half inch gap around the hole where the circulator goes in) will be negligible water loss unless you start talking m

Not terribly, rough fit (like, my tub has a half inch gap around the hole where the circulator goes in) will be negligible water loss unless you start talking multi-day cook times. I just cooked some meat for 24 hours and lost about 2~4% of the original water level