The amount of salt needed to properly recharge a water softener is mostly based on the amount of resins being recharged.
3/4 cu.ft. resin = 6 - 9 lbs.
1 cu.ft. resin = 8 - 10 lbs.
1.5 cu.ft resin = 12 - 15 lbs.
8 lbs. of salt for 8" x 44" tanks,
9 lbs salt for 9" x 48" tanks,
12 lbs. salt for 10" x 54" tanks is average.
If there is a lot of iron ( over 2 ppm )
or if the water is really hard ( over 30 grains ),
then 2 - 4 lbs. extra should be used.
So, an average residential system will use 6 - 12 lbs of salt per regeneration at least once a week.
Very hard water, or water high in iron, may require regenerating every 2 or 3 days.
The result is you will be using at least 30 - 40 lbs. of salt per month if hardness is not too high, or amount of water used low.
Well water ( usually very hard and often containing iron ) will commonly require using 80 - 120 lbs. of salt per month.
Simply multiply the pounds of salt per regeneration times the number of regenerations in a month to calculate your monthly average usage.
P.S. If you run out of Salt, don't expect to have soft water after a few days. And it may take more than one regeneration to get the water feeling soft again once you've added salt.
I recommend keeping the salt level above the water level in your Brine Tank.
When you start seeing the water level ( normally between 6 - 12 inches ) then it's time to think about adding more salt ( 40 - 120 lbs. ).
Does it matter which type of salt is used? Pellets or solar salt crystals? Is one better than the other?
Either will work.
Below is a photo of a "Starved" softener
Recommend the solar salt crystals as they dissolve 100%, as opposed to the Pellets that leave an un-dissolved residue in the bottom of the brine tank. And this residue builds up until it clogs the flow of the brine water in and especially, out of the salt tank, requiring that the tank be dumped, emptied, and re-filled with new salt ( plus 4 gallons new water ) every 1 - 2 years on average.
-- These "crums" under the water are not going to DISSOLVE enough ( or at all if "old" ) to make a strong "brine solution" to Recharge the RESINS ( the KEY to Soft Water ).
In simplest terms:
The Control Valve should be adding 3 - 4 gallons of water at the end of regeneration process ( Brine Refill ). A level of 6 - 12 inches, depending on the amount of salt in the brine tank, and the shape of the brine tank ( square or round ).
During Brine Rinse ( long 50 minute cycle ), the valve should suck out the 3 - 4 gallons of water in about 20 minutes ( less than 1/4 gpm ), and once water level drops to the last couple of inches of the salt tank, the "air check" will close off, to prevent any "air" from getting sucked into the Valve. The Brine Rinse ( slow suction and slow rinse ) will continue for another 30 minutes, as it slowly rinses the salt water through the Resin Tank, allowing it to Recharge the Resin beads.
How Much Water Should be in Salt Tank Video
What type of Salt to Use Video
How A Water Softener Works
Sodium Levels in Water when Softened
NOTE: Have the names for System Saver II, Rust Remover, and Solar Salt changed?
Yes, System Saver II has been renamed Clean and Protect™ and Solar Salt has been renamed Pure and Natural. Rust Remover has been renamed Clean and Protect™ plus Rust Remover™ and has been reformulated to not only remove 15 time more iron then plain salt but also extend appliance life. Also, the artwork has been updated for all of the products.