UTEX sells Soilwater: GR+/NH4 Medium at 1X concentration only. Stock solutions and individual components for this specific medium are currently not available for purchase.

Soilwater: GR+/NH4 Medium

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Soilwater: GR+/NH4 Medium

The basic garden-type soilwater; includes a pinch of CaCO3, which is added to the soil and water after steaming; suitable for most phototrophic freshwater algae. Optional ingredients: add Vitamin B12 to cultures of Volvox; a pinch of NH4MgPO4•6H2O added to soilwater cultures of Botryococcus, Synechococcus and some Euglenoids enhances growth and to LB 826 Gonium pectorale increases the numbers of 16-celled colonies formed.


For 200 mL Total
  1. Prepare Soilwater: GR+ Medium
  2. Add pinch of NH4MgPO4 after pasteurizing.

# Component Amount Stock Solution Concentration Final Concentration
1 Soilwater: GR+ Medium 200 mL
2 NH4MgPO4
(Sigma 529354)
1 mg 0.04 mM

Important Notes To Consider:

  • The quality of water, including natural seawater, is important. The term 'dH2O' generally refers to distilled, deionized, distilled/deionized water, Milli-Q water (Millipore Corp.), etc. Natural seawater and natural freshwater should be obtained from a non-polluted source.
  • When dissolving chemicals, wait for the first component to dissolve before adding the second. Stirring, and sometimes the addition of heat, is often required to dissolve the chemicals efficiently. Preparation of stock solutions for frequently made algal culture media make preparing media convenient but also necessary to avoid errors from weighing very tiny amounts.
  • Attention should be given to the pH of the final medium. In most cases, if pH adjustment is required, this occurs before sterilization. Please note that autoclaving removes carbon dioxide from media lacking carbonate stabilizing buffers. This would make the medium very alkaline soon after removal from the autoclave. In these cases, you should wait approximately 24 hours for gaseous equilibrium before inoculating the medium.