basic dilution question for making gels - (Jan/23/2008 )

Hello,

Really easy question but I wanted to double check. I have flasks of 200mls of 2% agarose gel already made up but I need to have that diluted to 0.8%. Can someone run me through the steps required to make that dilution? I need to know how much TAE to add to lower the concentration. i thought that it was a simple C1V1=C1V2 but then I get that I need to add 300mls of TAE and that seems like way too much.
And would I need to add more EtBr after I add the TAE?

Thanks...

Your calculation is correct. In principle yes, if you needed to match exactly that EtBr concentration, however it would likely make little difference, since the EtBr is typically present in vast excess.