| | Re: glutaraldehyde instead of excel
I don't think I would use it. From the information that I can find, the ingredients in the "activator" are:
40% potassium acetate (which should be non-toxic) and
30% Polyphosphoric acids, esters with triethanolamine, sodium salts (the esters with triethanolamine may be toxic to fish)
I am not a chemist, and and it would depend upon the concentration of triethanolamine, but I would exercise extreme caution.
Possibly another member who has had this happen will relate their experiences.