Need advice re: heater/pump/filter combo

Hi! I just moved to N Oregon from Calif & I'm setting up my hot tub - an older cedar 800 gallon number. I ran a freestanding Laars Lite heater 125,000 BTU on it for 12 years, with a 1 1/2 HP Starite pump and cartridge filter. The heater circuit board has gone, & I want a 2 speed pump for freeze protection cycling, so I'm in the market for essentially a new mechanical system. Reading online there's a lot of new technology out there - confusing, & hard to figure out what is best for me. I'm wired for 220, and plumbed for natural gas. Ideas? Advice? Thanks in advance, David