SFR (Service Flow Rate) is a number of how much flow you can put through a softener while maintaining good softening.
While I cannot point to documentation, common sense to me says that with high-hardness water, more time in contact with the resin ought to be better. So it seems to me the SFR numbers should take into account the hardness. Yet I cannot find a reference to that. http://www.qualitywaterassociates.com/softeners/sizingchart.htm says
I am suspecting those figures are a simplification in that if you had 100 grains of hardness, a given softener could not soften to less than one grain of hardness at the same flow rate as it could at 7 GPM. I understand that a single number is much more user friendly, at some point a compensation factor would seem to be called for.
Comments?
While I cannot point to documentation, common sense to me says that with high-hardness water, more time in contact with the resin ought to be better. So it seems to me the SFR numbers should take into account the hardness. Yet I cannot find a reference to that. http://www.qualitywaterassociates.com/softeners/sizingchart.htm says
The constant SFR gpm of most softeners is: 1.0' cuft = 9, 1.25' = 10, 1.5' = 12, 2.0' = 13, 2.5' = 18, 3.0' = 20, 3.5' = 22 gpm, 4.0 = 25 etc..
I am suspecting those figures are a simplification in that if you had 100 grains of hardness, a given softener could not soften to less than one grain of hardness at the same flow rate as it could at 7 GPM. I understand that a single number is much more user friendly, at some point a compensation factor would seem to be called for.
Comments?
