I have been using Glut instead of Excel for about 6 months now and I find it works as good as Excel both as a source for carbon and as a algae inhibitor. I buy mine here: http://www.emsdiasum.com/microscopy/...raldehyde.aspx
. See post #114 on page 12 of this thread for information as to price and more importantly, hazmat and shipping costs. BTW, Excel contains 1.5% glutaraldehyde.