I have a 2003 Landmark S Hot Springs Spa. I bought it used and ran it successfully for a few months. Deciding that it needed some basic maintenance, i turned off the power from the breakers, drained the spa and removed the 5 filters. They were quite dirty so i decided to completely replace them (not knowing how old they were). I bought 5 replacement filters of identical brand/model, inserted them in place of the old filters, filled the spa and turned it on from the breaker box. The tub turns on fine, the jets seem to be working well as usual but i am not getting any heat. I set the temp to 100 and allowed the tub to run for a few hours but no luck. I assume it must be filter related and/or i have fooled the hot tub into thinking that the high temp is tripping. What are the recommended steps to ensure that i have replaced the filters correctly? How should i get the heat back on? All was working well until i decided to do routine maintenance.