Does the water circulate in there?

No. We hear this question from people that think a system like this (without a heat system) is an economical way to keep water from freezing. However, circulating water would require a pump running at all times to circulate water. Also, with no heat or warmer water being added, eventually even circulating water will freeze. Ritchie WaterMaster and CattleMaster can be constant-flowed in lieu of heat, with this water draining to waste, or to a reservoir or pond.