Yes, I obtained the same volume. I might used degassed water (to minimize oxygen), and I would probably store in the freezer. I would probably divide the solution into smaller portions (aliquots). I would probably adopt the rule of tossing an aliquot after one use. These are general principles; I don't have specific knowledge of glutaraldehyde. I can imagine that there is an additive that would help, but I don't know of one.