I have a Fleck 7000SXT 1.5 cu ft system with SST-60 resin preceeded by a Fleck 7000 1.5 cu ft Centaur GAC filter, installed 6 months ago. My water hardness is 7 - 8 GPG, so I had it set to 8 GPG, regenerating with 6 lbs/ft to accomplish 33K capacity.
Today, for the first time, at an indicated 700 gallons remaining (typical capacity is around 3,800 gal), I took a shower in hard water. I grabbed the Hach 5B test kit, and it indicated 25 GPG from the indoor (softened) plumbing !! Is this typical behavior when a softener has exceeded it's capacity - it starts shedding hard water ions? I started a manual regen before I left for work this morning, but clearly something is not right, even if it is just mis-programming for changed conditions.
I didn't have time this morning, but when I get home tonight I'll check the incoming hard water hardness and see if it has increased. My municipal water supply gets water from both underground and surface reservoirs, so there could be some hardness variation throughout the year.
I have heard one esteemed participant on this board suggest two back-to-back regenerations at 15 lbs/ft to recover from exhausting the resin. That's a lot of salt. Is this necessary or the best way to fully regenerate the resin after this problem?
One last question: I am using 10% reserve safety factor. Is 10% deducted from the available capacity, so 3,800 gallons represents 90% of actual capacity? Or is that showing 100% capacity and I should expect a regen at 10% left, 380 gallons?