1. Weekly test the water chemistry for balancing.
2. Monthly clean the spa filter (cartridge type),
Pools back wash clean pool filters when (PSI) gauge changes (+ / -) from normal operating pressure.
3. Quarterly replace the spa water,
and For pools replace the water every 3 to 5 years, if allowed in your area, or recycle the water with a special filtered service. This can be tested with a (Total Dissolved Solids) TDS test.
* Heating Troubleshooting
The most common no heat problem is the water flow is too slow,
1. Checking for sufficient water flow at filter on portable spas is by removing the filter (cartrdge type). You'll possibly getting an error message at the display readout, please remove the filter cartridge if that's the type of filtering system you have, and reset the GFCI circuit breaker. This tests to see if the message will go away, and tells us this is the problem. Clean or replace filter cartridge. Pools backwash or clean filter.
2. Checking water level at the intake/skimmer, and if its to low add water to bring the water level back up to where it normally belongs. If the water is to low at skimmer the water vortexes and sucks air and the pump wont fully prime up to its full horse power.
If these procedures doesn't resolve the no heat condition then you will need a service call from a technician.