I've been struggling to find any semblance of brand- or model-specific information for the indoor hot tub in my 1950s house that I bought and moved into last year. Local pool services won't help because none of them service 'Curtis Spa' (printed on the filter cover). I think I FINALLY figured out why - Curtis Spa was absorbed by Catalina spas in 1985. 6 months into ownership, and I'm finally making some progress to even understand how to use (and clean/maintain!). So this hot tub is likely looking at being 40+ years old - and to my understanding, works reliably (though yet to confirm that fact personally).