Glutaraldehyde is a very hazardous chemical to be playing with. Excel comes in a very dilute form, so the hazards aren't so bad, but industrial/medical strength glutaraldehyde comes in a high strength form that can do a lot of damage to your body. Excel is expensive, but damaging your eyes and lungs is much more expensive. If you buy Excel in gallon jugs, when it is on sale at BigAl's or Drs. Foster & Smith, it isn't really that expensive.