We only have experience in dealing with Rydlyme in the past year and a half on our 11000 liter/min brine flow heat exchanger. The heat exchanger is used for heating brine with steam and the brine side of the heat exchanger forms hard scale due to hardness in the brine solution. We take the heat exchanger off line and circulate 50/50% Rydlyme for 4-6 hours to remove the hard scale from the heating surface to improve the efficiency of the heat exchanger. Rydlyme has worked well for our application and the best part is that it is environmentally friendly and it can be disposed through sumps in our plant. We used Hydrochloric acid before we tried Rydlyme and it had fumes and burn hazard to human skin. Rydlyme is safer than Hydrochloric acid to handle and user friendly. We are happy with the results produced by Rydlyme for our application.  – Yogi at Potash Corp SK