Axiom’s Puropal 300 (pictured), 500 and 1000 disposable cartridges are ideal for demineralizing fill water for closed-loop hydronic systems. The demineralized water meets the strict water-quality requirements from boiler and glycol manufacturers. It removes all the aggressive salts which specifically attack metals. It also removes scale-producing ions. In addition, it lowers electrical conductivity, which reduces corrosion. The 300 media changes from blue to beige when spent. It is an economical and convenient alternative to pre-blended glycol, and It features an optional conductivity and flow meter.