When you say "dissolve," do you really mean 100% of the salt turns into liquid?
Each gallon of water, will dissolve a maximum 3 lbs salt, creating liquid salt brine. Water will be fully saturated at 3 lbs, so it is the full strength liquid salt brine that is utilized to regenerate the resin's capacity. As it takes a little time to dissolve 3 lbs per gallon, that is why when fresh water enters the brine tank, a 1-hr delay was suggested before performing any further manual regeneration.
While you may add 3 or more bags of dry salt into the brine tank, your 5-minute brine fill setting will cause 2.5 gallons water to enter the brine tank, which will result in only 7.5 lbs salt to become dissolved into liquid brine each cycle. 7.5 lbs salt is appropriate to regenerate 23,000 grains capacity as per the 23K Capacity setting recommended.
As the quantity of full strength brine is directly conditional on the amount of capacity to be regenerated, when there is insufficient brine available to regenerate the full amount of previously depleted capacity, then a reduced amount of capacity will be regenerated, thereby leaving some resin capacity un-regenerated and providing little if any hardness reduction benefit.
Because 1 ft3 resin has a maximum total hardness removal capacity of 32,000 grains, even as your 23K capacity setting should cause regeneration to occur when no more than 23,000 grains capacity has been depleted, you said there were occasions when there was insufficient or no salt within the brine tank. This then will signify all 32K grains capacity will have been depleted, but the 2.5-minute BF setting will result in regeneration of ~23K grains capacity during the 1st regeneration cycle after sufficient salt is made available.
Since the remaining additional 9K grains capacity is beneficial to reduce ongoing hardness leakage, the 2 back-to-back manual regenerations detailed above, will cause regeneration of 32K capacity, thereby resulting in all of the remaining resin to remove hardness, instead of only a portion of the resin. With hardness being removed throughout all of the available resin, hardness leakage will be reduced, thereby resulting in higher quality soft water.
To ensure the brine tank will always contain sufficient salt, suggest topping up each time once the top of the undissolved salt is reduced equal to or slightly below the top of the liquid normally within the brine tank.
In reviewing the settings you asked about in post #9, increase the Backwash setting to 10-minutes. The other settings appear to be correct.
