This is exactly why none of the professionals respect you on this or almost any other board you troll around on. Your lack of knowledge and your combative attitude make you very undesirable to discuss issues of a technical nature with. It is obvious by your statements that you dont even understand the principals behind variable brining or how it can be used in commercial applications, or even in residential applications that have excessively high hardness.
Now put your thinking cap on and try to follow along young Padawan.
A restaurant with 24 grains hardness operating hours exclude 2-4 in the morning (for arguments sake, lets not debate ridiculousness as you tend to try to do). BTW, I have installed thousands of single tank systems in small restaurants, so I may have a slightly better understanding of this then you ever will.
Hot water usage ranges from 600-1800 GPD.
Obviously the right equipment is a twin alternating design for multiple reasons. The high variance in water usage, the lack of efficiency on daily regeneration etc.
At 600 gallons x 24 grains = 14400 grains per day.
at 1800 gallons x 24 grains =43,200 grains per day.
In order to size a restaurant correctly with a single tank system, you must install a system that will handle at minimum a single days use of water. Regenerating a 2 cu. ft. softener with a relativiely efficient setting of 8 pounds per cu. ft. will yeild 48,000 grains available capacity.
The old way was to simply have the system regenerate daily regardless of water usage, no meter needed. This would ensure soft water all the time, but it is highly inefficient.
Putting a meter on this unit without variable brining can create a whole new set of problems. Reserve capacities would have to be set so high that the system will simply regenerate daily, so the meter becomes a waste. If the system does not regenerate daily, the chance of hard water greatly increases if the system has a low water usage day followed by a high water usage day. (consider Thursday, regularly a slow day at the reataurant, Friday is typically one of their biggest days).
Now to the variable brining calculations and design.
Thursday, the system regenerated Wednesday night, night, giving the system a fresh capacity of 48,000 grains for thursday. thursday, the water usage of 600 gallons occurs, remove 14,400 from the capacity leaving 33,600 grains available for Friday. This would not make it through their heavy water day of 1800 gallons (43,200 grains needed), they would be short nearly 9,600 grains, or 400 gallons.
Variable brining will simply recharge the softener on Thursday night, but instead of using 16 pounds of salt, it will only regenerate with 30% of that, bringing the system back up to its full capacity for the following day.
Is that math simple enough?
You have a strange inability to be taught. I train on variable brining, I do not like variable brining in general, I feel too many companies rely on it when a twin alternating system should be used. Their are many minor problems associated with variable brining that most people dont want to discuss because it would take away from the "super efficiency" of the variable brining. Most variable brining systems are no more efficient than a properly sizeed (regenerate weekly) system. This would get far too technical to discuss on this board, but if you have an interest, i will probably be putting on a training seminar in Florida in late Spring / early Summer of 2013, you are welcome to attend.