UTEX sells Chu's Medium at 1X concentration only. Stock solutions and individual components for this specific medium are currently not available for purchase.

Chu's Medium

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Chu's Medium

Modification of Chu No. 10 (Bold and Wynne 1978). Suitable for some xenic cultures of Cladophora, Coronastrum and Nostoc.


For 1 L Total
  1. Add 10 mL of Chu Stock Solution to 990 mL of sterile dH2O.
  2. Add sterile NaHCO3 to medium.
  3. Store at refrigerator temperature.

# Component Amount Stock Solution Concentration Final Concentration
1 Chu Stock Solution 10 mL/L
2 NaHCO3 (Fisher S 233) 1 mL/L 1.26 g/90 mL 0.17 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.