The present invention relates to a water treatment unit for improving the quality of water in a water system and a water treatment system comprising the water treatment unit. The water treatment unit comprises a housing comprising a container, a magnet, a sacrificial anode, and a filter element. The container has an inlet and an outlet configured to allow a flow of water into and out of the container. The magnet is configured to attract ferrous particles and retain the ferrous particles to remove the ferrous particles from the flow of water. The sacrificial anode is configured to provide cathodic protection and scavenge oxygen from the flow of water. The filter element is configured to remove detritus from the flow of water. The magnet, sacrificial anode, and filter element are located within the container.