Is the water cooler pre-coating done during the startup of the unit?

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Is the water cooler pre-coating done during the startup of the unit? This is how we do it: we clean the surface before parking and before driving; after that, we apply a pre-coating. The circulating water system is cleaned using chemicals, and the water used in the replacement process is also cleaned. Once the total iron concentration in the water reaches around 1 mg/L, the replacement process is stopped, and we can proceed to the pre-coating stage. Anhydrous calcium chloride is added to the water intake at one time to bring the calcium ion concentration in the circulating water to 50–70 mg/L. Then, 150 mg/L of sodium hexametaphosphate and 40 mg/L of zinc sulfate heptahydrate are added. After 0.5 hours, sulfuric acid is added gradually to maintain the pH of the circulating water between 5.8 and 6.8. The system is operated for 8 hours; thereafter, no more acid is added to control the pH, and the system continues to operate for another 40 hours. When the pH value reaches 5.8–6.8, test strips are placed in the tower tank to monitor the pre-film formation effect.