You would have to dilute the glutaraldehyde with water, comparable to what products like Seachem's Excel or API's CO2 Booster do. The only ingredients in both are glutaraldehyde and water; Seachem term the chemical polycycloglutaracetal but this appears to be their form of glutaraldehyde.
The problem though is the glutaraldehyde. This is a very toxic chemical that is used in hospitals to sterilize medical instruments, in anti-freeze, in embalming fluid (it kills bacteria), in ship ballasts to kill bacteria, etc. It is dangerous to humans if it gets on your skim, or the fumes are inhaled, as this data sheet indicates: http://www.seachem.com/support/MSDS/...hExcel.doc.pdf
Some plants will be killed if Excel or CO2 Booster are used even at recommended strengths. If it is overdosed, plants, bacteria and fish can be seriously affected and even killed.
The manufacturers of both products may say they are safe with fish, but any chemical substance that carries such hazards is not something I care to use.