The PHPLUSKIT-14 cartridge is a super high capacity, naturally occurring PH increaser. It is for general drinking water pH increase purposes. It can also be used as a reverse osmosis polisher if desired (installed at the last stage). Since it is sacrificial, the calcite acid cartridge will add 2-5 ppm of hardness to the water. This is also an excellent way to reduce the corrosiveness low TDS water. This filter is constructed totally from FDA grade materials and media. This calcite filter will deliver a neutral effluent form acidic feed as low as pH5. Low pH''s require slower flow rates. One of the advantages of Calcite is its self-limiting property. When properly applied, it corrects pH only enough to reach a non-corrosive equilibrium. It does not overcorrect under normal conditions. Upon contact with Calcite, acidic water slowly dissolve the calcium carbonate to raise the pH. Increase pH level of the water by adding calcium carbonate mineral back into the water Made of 100% US-made high purity calcium carbonate to effectively neutralize acidity Friction-welded construction with no glues or binder to provide reliable, no-leak seal. 1/4" Quick connection fittings for easy leak free installation A perfect add on filter to compliment any existing or new RO drinking water systemsWith John Guest 1/4" union connector and 10 ft food grade tubing