The formula for calculating the weight of antibiotic powder given a potency seems wrong to me. Should it be "weight = V × C / P" to get the weight in mg when C is measured by mg/L or mg/1000mL?
Labelling the plate like that will contaminate especially with slow growing bacteria. I guess I should skip it. I will be doing it with Mycobacterium tuberculosis
There are a densichek You take some culture and put it in a tube with saline medium. Then you place it in the densichek so that by absorbance it measures the OD at a 0.50