AlcaPure Post-Filter adds a small quantity of calcium and magnesium minerals to filtered water, giving it a flavor similar to your favorite bottled water: Alkaline (7-8pH), with helpful minerals added. 75-gallon per day. The Reverse Osmosis Membrane produces pure water 50% faster than most other under-sink reverse osmosis water filters. The pump-less operation makes the filtration process the quietest on the market without using any electricity. This lightweight system can be placed beneath the sink or held in place using velcro.