When transporting a saturated sodium sulfate solution, how should the mechanical seal and flushing scheme be selected?

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A saturated sodium sulfate solution was pumped using a centrifugal pump, at 104°C and with a pH of around 7. The pump used single-face SIC-SIC seals, without any flushing system. The following problems occurred during operation: 1. The seal life was less than 10 hours before it became worn out, resulting in severe leakage； 2. After shutting down and restarting, since the pump and pipes lack heating, the 104°C saturated sodium sulfate solution immediately crystallizes upon contact with the cold pipes and pump, blocking them and preventing the impeller from rotating. Proposed improvement measures: 1. Replace the mechanical seal with a double-face SIC-SIC design, with the seals facing each other and large springs used; it’s not clear what flushing method would be appropriate in this case The main question here is whether to use cold water or steam for cleaning? If I rinse it with cold water, I’m worried that crystals will form when the solution comes into contact with the cold water. 2. When shutting down and restarting, first supply steam to preheat the pipes and pump before starting the pump. I would like to ask the experts here for solutions to this problem; thank you all in advance.