spell "experience".
ignorance is on the informant that has bad information.
some people will have a cure for a problem, underwatering your plants causes undue stress, why do that when you can place a few pennies worth of perlite on the top of the soil, or use any other method that other members in this forum have been most generous to provide.
i water my plants every second day and i do not have gnats.
my soil had gnats in the 50L bags before i used the soil, it is a very rich soil and attracts these gnats as there is a lot of rotting plant matter in the soil as well as other rotting nasty stuff that our type of plants love to feed on.