I tested the alkalinity of the water with test strips. It really increases the alkalinity compared to our unfiltered tap water. However, the top cap has a fancy lid that requires you to press down on a self-sealing lid to fill it with water. A little annoying, but not critical. Also, these are the cheapest "alkaline" replacement filters I've been able to find.
Filter under the sink Aquaphor OSMO-Crystal 50 version 4M with reverse osmosis white
39 Review
Filter under the sink Geyser Standard for hard water white
36 Review
Filter under the sink Aquaphor OSMO 50 version 5
58 Review
Water pump Xiaomi Xiaolang TDS Automatic Water Supply white
133 Review
NANPU Air Drying System With Double Filters And Pressure Regulator Combo For Clean And Controlled Air Supply
18 Review
NANPU DFR-02 1/4" NPT Air Drying System - Double Air Filters, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl
20 Review
NANPU 1/2" NPT Air Drying System - 5 Micron Particulate Filter, 0.01 Micron Coalescing Filter, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl W/Metal Gauge
23 Review
NANPU Compressed Air Filter Regulator Combo: Brass Element, Semi-Auto Drain, 0-150 Psi Gauge, And More
21 Review