For those who asked about fluoride, and getting it out of the water, this is what I know about working for a short time with the purification industry:

Naturally occurring Calcium Fluoride is a dissolved solid. However, as posted in this thread, the type of Fluoride being added seems to be an acid. Maybe someone can comment?

Dissolved mineral solids (lead, aluminum) are partly removed with a 'Brita' type filter (a study shows ~67% for aluminum, probably similar for other D.S.). A Brita-type filter contains an element to 'soften' the water, this works similar to a whole-house water softening system, replacing hard minerals with a softer one, usually potassium. This process removes at least a small amount of the fluoride, I was told by the water purification researcher. Maybe someone on here with more knowledge can comment.

The taste of the water improves because the activated carbon in the filter, removes biologicals and chlorine, (but not chloramines, a potent chlorine-ammonia molecule which is difficult to remove, begun use in California when I was in the U.S. years back).

The only way I have been told to most reliably remove the dissolved solids, is with a membrane-type system, which pushes the water (usually under it's own tap-pressure) against a membrane. The water is usually pretreated by flowing through a sediment filter, then an activated carbon filter. Standard housings are available (there was a unit Costco was selling years ago when I was in the U.S. for around 115 USD). These cut down on the cost of replacement cartridges. For comparison, culligan systems can only use culligan cartridges.

Tested membranes can be found (look around) from some suppliers. Not all membranes are created equal, and output purity can vary from ~66% to +97%. Purity is also greatly affected by the differential between input pressure and output pressure - the higher the differential (high on input, low on output), the better the purity. For example, the Costco system and many others, have a problem where, there is a bladder tank on the output. This naturally, 'pushes back' on the output, as it tops off. This results in a drop-off in purity as the two pressures equalize. It also wastes a lot of water.

I think it's much better, for those conscientious folks on a budget, to use a simple 'sediment-charcoal-membrane-small charcoal post-filter' system, -without- a bladder; No bladder to periodically maintenance (and stuff DOES grow inside there!), and no back-pressure on the membrane. It hooks to the tap (COLD water only), and be used to fill jugs. The membrane should last for many years, with only the filters replaced about every 8 months to a year, depending on how much the system is used. Exhausting the cartridges, with no regular replacement, while being NASTY, can also destroy membranes. Many membrane-types require chlorine to be removed FIRST [by the activated charcoal]

Building: For those building their own system for drinking water for a few adults, use standard housings, one for the spun [graduated] sediment filter (if I remember correctly, the spun filter is graduated, which means it has less tendency to clog, going from 20 microns down to .5 micron, I THINK scratches head), and one for the carbon filter. 5.0 (that's FIVE) microns is good for the carbon filter. 0.5 (POINT FIVE) is not so good I've been told, as even with the sediment pre-filter I've been told they have a tendency to clog before they exhaust. The tested membranes you can find with a little research, and the post-carbon filter is simply an in-line (small) filter which improves the taste a little. For those with really low-water line pressure, a pre-pressurization pump can be used. When I was in the U.S., US Filter (usually listed under oil filters in the yellow pages) stocked all the standard housings and filters.

Regards to all