I do not have the article, but there was an university biologist/chemist professor in the hobby that had access to a high-powered microscope. He was studying the affects of various cleaning agents (bleach, H202, detergent, alcohol, etc) on filter socks.
He cut and treated pieces of the "dirty" fiber with each of the cleaning agents.
I do not recall the magnification, but he found live algae spores still alive after treating bleach -- just that they turned white, but clearly still alive nonetheless.
Of all his treatments, he found H202 (hydrogen peroxide) worked the best. It literally destroys the molecular structure of organic material (bacteria, algae, etc).
It kind of like age-old adage...."Pay it now, or pay it later". Just do it right now, otherwise down the road (6 months, a year), your system crashes and all the money you invested in fish, corals, etc. go down with it.