Hello inspiraller,

I deal with water filters on daily basis. In fact, I sell them, so I'll try to be as least commercial as possible, so everyone can benefit here.

1. DISTILLED WATER

Is generally not that great. There are many contaminants that get evaporated with water and become MORE CONCENTRATED when passed through a distillery. Complex chemicals, heavy metals and Volatile Organic Compounds to name a few. Even when you use the best machines out there that pass water through a layer of filters...and then a distillation process becomes a burden and a bottleneck.

2. REVERSE OSMOSIS (RO)

Wastes lots of water if used with a booster pump, but you can get a system without a pump that practically wastes none. Unfortunately, as goes the pressure so goes the quality of filtration. Besides other benefits or RO that everyone knows (it produces one of the cleanest waters out there), the drawbacks are low pH, highly aggressive water that needs to be neutralized or kept in glass container (NOT PLASTIC), impossibility to use on a whole house system, high susceptibility to bacteria contamination (especially the large water holding tank - bacteria LOVES these).

3. RE-MINERALISING - RE-ALKALISING

Not a filtration process, sorry. It is a POST-filtration.

4. KILLING BACTERIA / PARASITES

In a modern world, water companies do that with chlorine or chloramines. You can also use Ultraviolet (UV), but your water needs to be free of sediment, or it won't work.

5. GRANULAR ACTIVATED CARBON

ok, used everywhere for water filtration. Excellent absorbant

You've missed a whole range of systems. A typical modern water filtration system is a multi-stage system, consisting of the following:

1) sediment pre-filter - this is a 5 micron or less prefilter that removes dirt
2) Carbon Block or Granular Activated Carbon - 2 different technologies of using carbon.
3) a set of specialized filters to remove/reduce chlorine, metals Volatile Organic Compounds, reduce hardness etc. Typical technology includes: KDF (mix of copper and Zinc), Ion Exchange Resin.
4) contaminant-specific filters, such as fluoride removal, arsenic removal, nitrates removal etc. Typically it is an anion or other type of resin, synthetics activated alumina for fluoride removal, or other technologies
5) for well water - a bacteria removal system such as UV
6) for low pH - acid neutralizer cartridge. That is where Re-mineralizing happens as well. Not a filtration process, just water quality improvement.

etc.
Typically a good water filtration company can design a system SPECIFICALLY FOR YOUR WATER PROBLEM.

Ionizers, Ozonators and other holistic tools are typically NOT WATER FILTERS. They use different processes to change water chemistry slightly. They typically employ a water filter such as a combination of Carbon, Tourmaline and Coral Calcium (post-filter) in Jupiter Water Ionizers. But that is not because they are such great FILTERS, they need FILTERS to function. The water filtration process is better left to WATER FILTERS.

Yeah, don't know if I can drop URLS here, but if I can - please feel free to visit our water filters store at FilterWater.com . If I can't, moderators please just remove link and keep the post! Thanks