Just had my ac tech ask our chiller mfg what to product to use for cleaning the ac raw water system. The mfg said Trac Barnacle Buster! When we lost both chillers because of perforated tubing on the chillers we were told the Trac BB and Bromine tablets that we found on board after buying was the culprit. Go figure! Any solution that will dissolve barnacles, oysters, and heavy scale will likely corrode our cupronickel metal tubing over time. Like you said what else can we use and keep the system clean?