HDD to SSD, HDD fan was running full speed, so I installed

After getting my old (iMac mid2011) hard drive replaced with a new SSD, the HDD fan was running like crazy. So I installed Macs Fan Control. It shows the ODD running nicely at 997, in a range shown to be 1000-2500. The CPU fan is running nicely at 939, with a suggested range of 940-2100. The HDD fan was running at 5501-5510 with a range suggested at 1100-5500. (goin' like he!!! So after changing to an SSD, I didn't even think the HDD fan should even be running, but I set the speed to 4500 and it quieted down. How low can I run the HDD fn, and would resetting the PRAM slow/stop the HDD fan?

Thanks,

FRED