Your thought is correct, the larger the brine tank, the better. Their is no downside. Keep it full, when you are at home depot, grab a bag of salt.
Buying a bag when out to a big box store isn't much different than like once a month or so but, I think F6Hawk might be interested in buying salt as infrequently as possible.
Salt bridging is a rare problem and can usually be corrected by switching to a different salt type (pellet to crystal, or vice versa) or just program your control valve to do a brine fill first.
Briging is most prevelant in extremely humid environments, or in areas where there are extreme changes in temperature between day and night, and the brine tank is located in that environment. In a basement, you will be fine.
Usually pellets bridge long before crystal will.
You must be from a very dry low humidity area with little to no experience with salt bridging... like California. The majority of the rest of the US has some serious humidity. I know Central PA where I'm from does. I have seen hundreds of cases of salt bridging. And all those softeners were in a basement because the only residence without a basement in most of PA are cabins that are not full time residences. And the larger the salt tank the more likely bridging problems are.
One other problem with the larger brine tank, it is taller, lifting a 50 pound bag over the 40" tall tank can be difficult for grandma, so we will use 30" tanks for the older folks.
"One other problem" with a larger salt tank, what would the other problem be? I htuhgt you said there was no problem with larger and the larger the better.
As a side note, not critical to this discussion, but before someone jumps in with their personal attack/opinion, we use brine grids for marketing in residential applications, commercially, they allow us to use much smaller brine tanks especially on large equipment when there is limited space for the brine tank.
I have built brine grids that were 30 inches tall in a 60" diameter x 48" tall tank due to extreme space limitations. If brine grids were as important as some people claim, then why are they a rare feature on commercial equipment?
I haven't seen anyone say a grid is important but I see you used them too.
There is no negative wit hthe use of a grid.
A grid keeps the salt tank cleaner than without one. That reduces salt tank cleaning which is not a fun thing.
A grid prevents a lot of salt bridging problems; except in the few very low humidity areas of North America.
A salt grid usually adds about $10 retail to the price of a softener with a normal size salt tank, and a grid should last a couple decades since they started making them out of plastic about 25 years ago.
They are ideal with Pre refill/dry brining softener control valves. Next to no salt sits under water for more than a few hours except that being dissolved just prior to that night's regeneration.
You call it marketing but most of my prospective customers really liked the positives I've listed above. BTW, I can't think of any negatives to the use of a grid, can you?
OH YES!
A grid can help prevent salt tank overflow too. Especially for those folks that like to keep the tank full of salt.
That overflow thing is another reason to not keep a salt tank full AND to frequently check inside the salt tank and if you see water with a salt grid installed, there is a problem, either you need to add salt or to troubleshoot the softener for water going into the salt tank when it is not supposed to be, or brine not being drawn out during a regeneration as it should be.
Again before it gets lost, can you come up with any negatives of a salt grid in a residential softener?
Or, for a commercial softener or do you think the positives don't apply to commercial establishment softeners?
I didn't see anything wrong and saw all the advantages so I included one with all my commercial sales too. Especially if the softener was in a basement, commercial or residential, where no one noticed them for months (because they filled the salt tank only a few times a year) until the softener stopped working or someone one day nonchalantly asked why there was water all over the basement floor.
I, Gary Slusser, hereby Certify the above reply personal attack/opinion free.