At purchase, machines are often compared on price. In use, what weighs is the operating cost: cleaning-agent consumption, discharge handling, downtime for draining. That is exactly where closed-loop makes the difference.
Open loop vs closed loop
In an open loop, the bath loads with contaminant over the cycles, then gets replaced. In a closed loop, the cleaning agent is filtered and regenerated continuously: it stays usable longer, which stabilises the process and reduces draining frequency.
