Poor water quality can affect the O-rings on either side of the heater and also the heater element. Calcium can build up on the heater element making it more expensive and difficult for the heater to keep the water at temperatures up to 107 degrees Fahrenheit. That translates into a more expensive electric bill. By taking care of the water and pH balance, this problem can be minimized.
Another issue is that if the heater element touches the metal sheath or if there is another short inside the element or at the epoxy seal near the terminals, then the heater can short out and will need to be replaced.
Some may want to save a bit by just changing the heater element vs. the whole heater tube/manifold that contains the element. This is not recommended as early failure can be the result if the element is not properly installed. It can be a bit tricky to get the replacement right and sometimes the epoxy seal can crack or other damage can occur.
If the heater is more than a couple years old, it is a best practice to always replace the entire heater instead of just the heater element to avoid problems.
When sourcing a replacement heater, read the information from the current heater tube/manifold including the voltage and watt rating (usually between 1kw and 5.5kw). Also note the model number if any to be able to source the same heater.
Note that there are several different heater brands that will work as the same replacement. For instance Therm Product heater replace several Balboa heater models, many times at more affordable prices.
In any case it is also great to order the replacement heater online to avoid wasting alot of time driving around from place to place in search of a particular heater model. The fastest growing online retailer that stocks almost any heater online is Hot Tub Outpost. They offer both the Therm Products version as well as the brand name Balboa, Gecko or other heater brand.
Get free shipping too on almost any replacement heater! No tax either for most states and great prices to make it worthwhile to just change out the whole heater tube instead of the element. Plus, that way the problem is solved and the entire heater is good for many more years. You may even save on electricity if there was some buildup on the old heater element.
Lastly, replacing the entire heater tube is much easier than replacing just the element. In all cases, always turn off power to the spa and verify it is off before beginning with any heater replacement.
Can the water stay in the spa while the heater is being changed? Well if the water has been in the spa for more than a month, why not just drain it and make things easy. Otherwise, some spas do have service valves on either side of the heater that can be shut off so the water does not drain into the heater area, making this type of service possible without needing to drain the spa.
Don’t forget to turn the valves back into the full open position when done!
Checkout Hot Tub Outpost for more information on replacement hot tub heaters.