Date: Fri, 19 Sep 1997 17:35:42 +1000 From: Andrew Bernuetz <andrewb@camden.usyd.edu.au> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3594$foo@default> Subject: Re:CP TC media problems
Carl wrote:
>The last 3 batches of media I have made have had the consistancy of runny
>pea soup when cooled. I'm not sure what I'm doing wrong. I have made the
>same media successfully 2 or 3 times previous with no problems. The other
>times, I made it 500ml batches, no problem, the last 3 batches were 1 litre
>batches. I can't believe that making 1000ml instead of 500ml is going to
>do that unless my agar measurements are out of line!
I agree.
Have you used the same batch of agar? Batches bought from food stores are
not guaranteed in quality and you may need to use more.
Have you checked the pH? I recently made some plain MS media with 6.5g/L
agar at pH 3.0,
this did not set!! Perhaps your water is of inconsistent quality, throwing
your pH out. I am not sure at what pH agar will not set, but I presume it
may be somewhat higher than 3.0.
>Who knows, maybe its suposed to have that consistancy, and the first
>few times when I made half litre mixes, I put 6 grams of agar in by
>accident, who knows!
That is possible (but three times?), however, try keeping a note book with
the media ingredients written down with the correct amount calculated for
the volume you are making. Don't assume that you will do the calculations
as you go, as this very frequently results in mistakes (believe me!). Also
note anything different that may have happened, or you may have done
differently, even if you do not think it is all that important. This way
when a problem strikes you can easily refer back to what you did and
perhaps solve the problem.
Good growing,
Andrew Bernuetz
andrewb@camden.usyd.edu.au
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