Which of the following indicates a malfunction in a sodium zeolite softener?

The indication of a malfunction in a sodium zeolite softener is the presence of water hardness. Zeolite softeners are designed to remove hardness-causing minerals, such as calcium and magnesium, from water by exchanging these ions with sodium ions. When the system is functioning correctly, the water should be free from hardness.

If water hardness is detected after passing through the softener, it suggests that the resin beads within the softener may be exhausted or not functioning properly, allowing hardness minerals to remain in the water. This degradation in performance is a clear sign that maintenance or regeneration of the softener may be necessary, as it is not effectively completing its intended task of softening the water.

In contrast, high sodium levels can occur as a normal result of the softening process, while low pressure is often unrelated to the softening capability. Enhanced clarity of the water could indicate proper function or other factors unrelated to sodium zeolite softening capability.