from 7 0 to approximately 7 9 during the experiment 0092 time temp as min activity ph u00b0 f lab notes mg l u2212 25 add 2 l of wharf water to 5 jars 9 02 68 yellow tinged 0 112 water u2212 15 add several drops 12 n hcl to each 7 00 jar 0 increase speed of mixing unit to 300 rpm 0 first jar add 0 05 g fe grade b dry 7 92 yellow tinged and 0 025 g s dry powdered water 0 second jar add 0 038 g fe grade b 7 91 yellow tinged dry and 0 019 g s dry powdered water 0 third jar add 0 025 g fe grade b dry 7 85 yellow tinged and 0 0126 g s dry powdered water 0 fourth jar add 0 0126 g fe grade b 7 92 yellow tinged dry and 0 0063 g s dry powdered water 0 fifth jar add 0 0063 g fe grade b dry 7 90 yellow tinged and 0 0032 g s dry powdered water 0 sixth jar add 0 0025 g fe grade b 7 89 yellow tinged dry and 0 0013 g s dry powdered water.