Hi, Russ and other forum members:
My apologies for not replying sooner, I was away for a wk.
I do not know any particular brand of ion-exchange filter, as I never used any.
I still believe that even the best filter of this kind does not offer the same protection as a simple addition of soluble calcium salt.
Tea leaves, for example, contain plenty of fluorides. And so if someone prepares tea with a fluoride-free water, he would still end up ingesting whatever came with those tea leaves.
But addition of soluble calcium salt would do the trick for both ingredients - water plus whatever is added to it (tea leaves or smth else).
Wines contain fluorides, often very substantial amounts. Is anyone ready to forego wines and all social occasions it comes with?
But addition of soluble calcium salt would do the trick perfectly.
Beer, soft drinks and reconstituted juices would contain fluories, if they are prepared with fluoridated water.
You cannot run those drinks through a filter, but you can add soluble calcium salt and be perfectly safe.

Plus how about eating out? Here you got a glass of water in a restaurant, or a bowl of soup; what do you do with it?
I never touch water that is served in restaurants, just as I avoid drinking anything when at other people's places. I always carry my own water or I pour a solution of calcium acetate into the "3rd party water". I carry a small flask of it with me at all times.

Plus no matter how good is an ion-exchange filter, the active ingredient would inevitably begin to age after a period of time.
Imagine during the first week it was taking out 90 percent fluorides. Ans so instead of "optimally fluoridated" water with 1ppm you were getting 0.1 ppm of rat poison.
But what happens 3 months down the road? six month? a year?
At which point you would make a decision to replace your expensive machine (or a cartridge)?

Plus on top of that, in addition to the quality of ion-exchange resin, you still need "mechanical arrangements" to ensure maxium contact of water with those granules.
This is a very serious problem and the best illustration I can think of is the fact that bacteria and viruses pass just fine through a table-top carbon filter, since there is some "space" between individual granules.

Plus every individual ion-exchange granule would be "aging" at the surface. And here the manufacturer's specs can be twisted by saying that "this filter has enough ion-exchange material to remove X amount of fluorides".
In view of the fact that once the material got "clogged" on the perifery of each granule, whatever is left inside becomes pretty useless.

It is essentially the same with bones. Transformation of hydroxiapatite into fluoroapatite is taking place in areas, which are adjacent to the blood vessels, which are a part "biological matrix" of a bone.
So in terms of pure weight, only a few percent of a bone mass could have undergone this pathological transformation, and yet a person would be debilitated with chronic fatigue, since his calcium exchange would be severely compromosed.

so here are my 2c
best regards:Oleg