Oxygen dissolved in the water would normally be {HEAD ~ less than 8 pm} and a manually selected ratio assuming 8 ppm would be adequate for {TAIL ~ smaller installations} 
Oxygen dissolved in the water would normally be { HEAD ~ less than 8 pm } and a manually selected ratio assuming 8 ppm would be adequate for { TAIL ~ smaller installations }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL