HACH SC1000 Modbus registers

I am trying to connect to a HACH SC1000 sensor using the Modbus driver. My OPC item path is [basin]2.HRF400004. The tag values show true but I am not receiving any data. Is my format incorrect. It is modbus address 2 and I am looking at a float value. The 400004 address is from the manual. Has anyone made this connection before?

Your format looks correct besides the address. In this case the OPC item path would be [basin]2.HRF4 instead of 400004. The HRF indicates it is a 400000 or holding register.

That worked! Thank you for the fast response. You made my morning easy.