It is easy to replace the filters. Please follow the instruction on the purifier machine for HTW A-1. 

1^st stage: PAC composite filter element (Polypropylene folded fiber PP cotton +carbon rod). Removal of impurities such as silt, rust, sand, suspended solid; removal residual chlorine, heavy metal and absorption of disagreeable tastes and odors. Recommended replacement cycle 6-12 months.

2^nd stage: Reverse Osmosis filter element (200G Large Flux). Reverse osmosis (RO) is a pressure-driven separation process that employs a semipermeable membrane and the principles of crossflow filtration. Using high-tech reverse osmosis technology, the theoretical purification accuracy is 0.0001µm, and it can filter out harmful substances such as bacterial, heavy metals, scale, pesticide residues, antibiotics, radioactive particles, residual chlorine, microorganisms, virus, microplastics, and organic matter in the water. Recommended replacement cycle 12-24 months.

3^rd stage: Weak base strontium-rich. Rear composite carbon rod. Further remove different colors and odors in water and improve the taste. Weak alkaline, pH value can be stabilized between 7.0- 8.5. Rich in trace elements, strontium content reaches the national drinking strontium mineral water standard. The chemical effect is as long as 12 months. Then high- density carbon rod with a gap of about 3-5 microns can further remove residual chlorine and organic matter, achieve antibacterial, remove different colors and odors in water, and improve taste. Recommended replacement cycle 6-12 months.