I've been running my swim spa for 2 years now and it was hard find specific information for them. I ended up treating it like a hot tub and following the thread that mknauss linked for you.
One key is the Chlorine. Use chlorine with no additives, and know that all chlorine is not created equal. You need to know the strength. LIDL brand is what I use the most.. its 8%. The Ace Hardware brand is 5.5%, and stay as far away from the BiLo brand as you can ... it's like 3%. We've used the LIDL brand exclusively until recently with chlorine hard to find. I've resorted to the liquid chlorine that Ace Hardware carries at 5.5%. It's not actually "ACE Hardware" brand, but it's the generic brand they carry in my area. I keep my chlorine higher than normal at around 8 ppm, mainly because I'm not always reliable at checking every day. I typically add 24 oz of chlorine every 3 days or so and about 8 oz per person per hour after a swim. If you have an ozone generator then you have to watch chlorine closer. I think mine stopped working, but while it was running I was losing close to half of my chlorine per day, which is consistent with other posts I've read on these forums in the past.
I followed the procedures in the "How do I use chlorine in my Spa" thread and found that my PH stabilizes right around a Total Alkalinity of 50-60 . Once I hit that point I rarely have to do anything else. Add Chlorine on schedule and add a couple ounces (use pool math) of Muriatic Acid every week or so when PH gets high. I did add about 40 ppm of Borates (Boric Acid), so that is helping to keep my PH consistent. I'm mixed on it though, so I'm not planning on adding it for the next fill to see how things go.
When in doubt, follow the instructional threads. My experience above is just to give you an idea of how things have worked for me.