F/S Aquamaxx cTech T-1 Calcium Reactor. Purchased this for my system then decided not to use it and went with dosing A/B. This is new and never been used. Rated for tank up to 300G. Asking $150 shipped. Listed on Marine Depot for $199.99. https://www.marinedepot.com/aquamaxx-ctech-t-1-calcium-reactor