Mixing with distilled water or at least soft water prevents mineral sedimentation_precipitation. I've seen the results of long term use between using tap water vs soft water in the mix. Much corrosion when using hard water, like new using soft water (in a gas motor). I've been told the reason for antifreeze conditoners (water filters) is to maintain an additive to prevent micro bubbles from forming on the sleeves causing erosion_pitting. Antifreeze has a shelf life and should be replaced periodicly as routine maintainance. Ask a dealer, I've heard 5-7 years.