Reduce the size of water molecules? Utter nonsense. I doubt any
any filter could help add 'essential materials'. At best, it just
makes tap water closer to mineral water, by adding more minerals.
That's why it 'tastes good'. It's the minerals at work, esp sodium.
The only time when tap water taste bitter is because the water pipe
used is plastic.
Fact is, water quality in S'pore is best in the world. Any sort of
filter is quite a waste of money. Want pure water? Might as well
buy distilled water.