The Protium 3.0 Anti Vortex add-on is compatible with all versions of Protium including 1.0, 2.0 and 3.0. Occasionally when customers run the return inlet to one of the ports on the pump top, they are experiencing a vortex which pulls air into the loop (this usually happens with shorter reservoir tubes). It depends on the loop configuration. So, we have created the Anti Vortex to solve this.