Not sure what to do with Autotrol series 255 water softener

Every "water softener" needs a regenerate (salt or potassium) to clean the resin and restore the capacity. Think of the water softener as a large sponge. As with any sponge it can only absorb a certain amount of water before it is saturated and excess water runs off. The same is true for a water softener. Depending on the capacity of the softener 20k, 30k, 40k, 45k or 60k capacity it can only remove so much hardness before hard water begins to "bleed" through and come into home. I would suggest having the water tested (before softener) by a water treatment dealer or independent water testing lab to determine the water chemistry and the proper settings for your system and families usage.
For reference only lets say your water has 10 grains per gallon of hardness, 4 people in the home and a 30k capacity softener.
Formula: 4 people x 75gpd per person = 300 gallons used per day x 10gpg hardness = 3000 grains of hard water used per day. Keep a 20% reserve in softener so that gives us a practical capacity of 24k/3000=8. This softener would regenerate every 8 days. This system would use about 60lbs of salt per month. If the softener is still in service (not bypassed) all you really need to do is fill the salt tank (there should be about 10" of water in salt tank) you will need to take some of the water out of salt tank, if there is no salt in it. Use a good brand of salt like Dura Cube or Hardi Cube (available from water treatment dealers) add about an 1/8 cup of household bleach to salt tank (to sanitize the system this time only). Make sure the timer is set for correct time of day as these systems are preset to regenerate at 2am. Let the salt dissolve for at least 4 hours and manually regenerate the 2 times in 24hr period to regain capacity. If this is a metered system (runs by gallons used) it must be set according to the water chemistry and your families usage as in the formula above (8x300=2400 gallonsx10=24k). Here is the link to owners manual for your system.
http://www.pentairwatertreatment.com/PentairFiles/Pentair%20Water%20Treatment/Manuals/255%20400%20Homeowners%20Manual%201018075.pdf

I would suggest having a water treatment dealer inspect the system, test the water, sanitize it and set it up properly for you if you are not comfortable doing it yourself. You can go to www.wqa.org for a certified dealer in your area. Here is the link for (Pro's Pick) Dura Cube salt dealers in your area also.
http://www.cargill.com/salt/brands/pros-pick/index.jsp
Those are not naive questions. They are questions on point and I hope this information may help you in getting your system back up and running.
RJ

We would like to know of a dealer in our area for this water softener as it has not been serviced for 11 years -- no problems with it but we are getting older and would like a system that takes pellets instead of blocks. We live near Iowa, Wisconsin and Illinois. Any help would be so appreciated.