10L Media Kit: Bristol Medium

H.C. Bold's modification of Bristol's recipe (Bold 1949). General purpose freshwater medium that lacks vitamins and is the essential base component for other media such as Bold 3N and Modified Bold 3N Media (see table below).

Media kit includes all the necessary chemical components to prepare 10 Liters of Bristol Medium. All UTEX Media Kit solutions are shipped sterile and should be handled aseptically to avoid contamination.

Looking for Bristol Medium in 1-Liter and test tube volumes?

View/purchase prepared and sterile 1X Bristol Medium

Available Bristol Media Kit Upgrades

For similar chemical components but with 3X the nitrogen and the addition of vitamins, view the available Bold 3N and Modified Bold 3N upgrades for this kit. You can purchase the Bristol Media Kit with an upgrade at a discount using the 'Options' dropdown at the top of the page. Media Upgrade Kits are also available to purchase separately on their respective pages.

Medium At A Glance

  • Water Type Freshwater
    pH of Medium 6<ph<8
    Contains NO3


For 10L Bristol Medium Total Volume

  1. Obtain and wear the appropriate PPE.
  2. To approximately 8.4 Liters (8,400 mL) of dH2O, carefully add the entire bottle of Bristol solution while stirring.
    • Bring total volume to 10 Liters (10,000 mL) with dH2O.
    • Cover and autoclave or filter-sterilize if non-sterile water was used.
    • Store at refrigerator temperatures.
    Components In Kit
    Final Concentration
    NaNO3 2.94 mM
    CaCl2•2H2O 0.17 mM
    MgSO4•7H2O 0.3 mM
    K2HPO4 0.43 mM
    KH2PO4 1.29 mM
    NaCl 0.43 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.