Preparing a saturated salt solution for regulating incubator relative humidity for maintaining adult workers in the laboratory

The following is an example of how to create approximately one litre of sodium chloride saturated salt solution:

  1. Heat one litre water slowly in a two litre glass beaker.
  2. Place beaker on standard laboratory magnetic stirrer.
  3. During heating, gradually add ~400 g sodium chloride to water until crystals do not dissolve any further; this will slightly increase the volume of the solution.
  4. Mix solution using stirrer.
  5. Continue adding sodium chloride until a gentle boil is reached and no further salt will dissolve.
  6. Remove solution from heat, pour in appropriate, open-mouthed basin, and let cool before transferring to the incubator. Solution should contain a mixture of crystals and liquid.
  7. Use salt solution for multiple weeks; replace when no water is present or when fungi or bacterial growth occurs.