Glyoxal is a safer substitute for formaldehyde. Formaldehyde is a nasty dangerous substance and should be avoided at all costs by alt photo workers. It is carcinogenic and moderate exposures can cause emphysema and other lung problems.

Glyoxal can be used in equal proportions in most formulas.

Glyoxal is not 100% safe, not much in this world is, but it is far safer to use than formaldehyde.