When we are talking about enjoying your bubbly relaxing hot tub, warm water is what you are looking for. If your heating element is not working properly all you'll have is a cold tub of water. Heating elements have several factors that can contribute to a shorter lifespan: poor water chemistry, high mineral content in water, low water flow and air inside heating chamber.
Poor water chemistry plays a role in the expectant life of your heating element like other parts in your spa - low pH, low alkalinity and high water hardness levels can lead to the premature failure of your heater. Corrosion, a rusting effect that happens to iron rich metals, can occur when the water becomes too acidic. Low ph, a high total dissolved solid or high mineral content can speed up the corrosion process. Doing an initial and weekly water chemistry test can help you to correct chemistry imbalance, and keep your pH, alkalinity and water hardness at appropriate levels.
In areas that have hard water, or when you are filling straight from a well you can have high levels of metals and minerals in your water. Calcium and lime can collect on the heater element surface creating a white coating. This layer of scale will slow heat conversion which makes the heater less efficient, have a higher internal temperature and longer running time. The white coating does not let heat escape properly and over time the element burns itself out. Using a pre-filter when filling your spa can help to remove these particles before they enter your hot tub, helping to reduce the potential for build up on your element.
Air bubbles and air pockets can also play a huge role in reducing your spa elements life. Air that comes in contact with the heating element allows the outer covering to heat unevenly, breaking down the protective covering and exposing the filament inside. When there is little to no water flowing through the heating tube or you have an air lock, the air becomes trapped and the heating element can burn out in a very short amount of time, sometimes as little as a few seconds or minutes.
The heater is a crucial part of the inner workings of your spa, and keeping it in good working order is important. Making sure you are aware of potential problems before they start can save you money, time and extend the life of your spa parts. Keeping an eye on water chemistry, mineral and metal content of water and ensuring water flow is correct will keep you enjoying your hot tub longer.