Another Water Softener Question

I am a newbie here so be gentle. I need some insight into replacing my current water softener. Back around 1987 I had a home demo from a Rainsoft dealer and was really impressed until I got the $3000 price (I'm a cheap SOB). I decided to look around and bought a unit from Home Depot that I think was a Star brand they sold at the time. I installed it myself and it worked for about 10 years but started to not recycle by itself, so I went back to HD and bought a GE Smartwater single tank GXSF39.. single tank and installed it myself also. It lasted with a few problems until last week.

I noticed that the flow rate was diminished and thought it was my whole house filter (also HD from GE) and changed the filter. It helped for a while but as the water flows, it gets progressively slower. While filling the washing machine it slowed to a trickle. I switched the GE WS bypass valve to bypass setting and the flow jumped up to where it should be so I figured the resin in the WS was clogging the flow somehow.

I also had problems about 8 months ago with the Pot Chloride salt I use turning into a rock at the bottom of the brine tank and not allowing the unit to regen right and the water got hard even when I manually regenerated several times. I drug it out in the driveway and emptied the salt and brine out. I laid it over on its side and slid the resin tank out to clean out the solidified Pot Chloride (I took the valve apart on the top of the resin tank and removed it). After washing out the tube and float and cleaning the brine tank, I re-assembled everything and added Pot Chloride and recycled several times. The water was soft and it worked for about 6 months when another salt rock happened again and I repeated the process of cleaning it and it worked fine for a month or 2 when the flow rate decreased. I switched back to regular softener salt (NaCl?) after the 2nd cleaning when the low flow happened.

Sorry for the long dissertation but I'm an Engineer and can't help myself.

Now for my question. I went back to Home D and they carry a newer model of the GE but I wanted to look around for maybe a better unit. I went by Sears tonight and the Kenmore units there have the same control head as my GE has. I found a place on eBay that sells GE Logix, 2 tank units. So is there hope for my old clogged GE and what could cause the low flow? I think the little turbine wheel in the outlet pipe does not rotate freely and my regen times are getting long, but I could try to remember to regen manually every 3 days or so.

I did read several pages of discussions here about the merits of the GE Logix units and others and I wanted to see where I could get a replacement softener for a decent price since all the plumbing is in place. Thanks for any help.