Thank you, Old-Biscuit, for your quick reply. Now that you've done the calculations for me, I see why we haven't had to regenerate yet. I was testing the water in every campground but when we got to River Island State Park, which is right on the Colorado, we know how bad their water is.
We absolutely love our water softener. The main reason we bought it was to try to prolong the parts on our Twin Temp hot water/furnace system. With the hard water, normally in six months our mixing valve gums up with calcium and we have sporadic hot water and need to find an RV shop to fix the Twin Temp. Not all shops understand the Twin Temp system, so sometimes this is a difficult repair. We don't know if its helping the mixing valve but all the other benefits are wonderful; lots of soap suds, soft skin, no calcium ring around the sink and shower, no plugged faucets, etc. We also use the softened water to wash the truck to stop the water spotting.
You bet we love our water softener!