Heat Exchanger for closed loop cooling

I understand you have a unique situation. I was trying to minimize my water use during the drought here and contacted Salt Away. They suggested drawing water from one barrel with their product and then capturing the exhaust water. By recycling the flush water I could accomplish the task with a minimum of supply. Interesting concept. They claimed that I could reuse the water a few times, but weren't very specific. How many times could one re use the flush fluid? I dropped the idea and just focused on keeping my flush time short, but what looks to be effective. I always wait until I'm getting strong flow in bursts out the exhaust at idle.  Any flush is better than no flush.