Fluconazole is neither snake oil or an algicide. It is a fungicide and it works.
Spent a year battling algae your way. Found that the cleanup crew - snails crabs and lawnmower blenny (as my tank is too small for tangs) did not bother with the algae once it had any length. Nitrates and phosphates were zero because of algae so couldn't control. Removed rock for manual scrub but because of texture was not able to remove all of it and it was a lot of work.
Was ready to shutdown tank so used fluconazole as a last resort. 9 days in 95% of algae gone, nitrates and phosphates are reading again. As it is a fish medication the fish seem unbothered. Only have zoanthids but they improving because they are not living in a mass of algae.