I keep hearing about people making that mistake. Treating it like coco will not work and there's not enough sticky traps on earth to get rid of the gnats. The only reason I am even thinking about switching to pure coco is the cocoloco has a bit more N then I like. Gnats love the organics. Maybe pure coco is not so bad? IDK
FWIW my buddy who grows in pure
canna coco never gets bugs. I am about 2/3 of my way through a cycle running coco, also no bugs... knock on wood. We both irrigate up to 4 times a day.
If you want to avoid fungus gnats and root aphids, keep the grow room clean, never wear outside shoes in your grow, Avoid soil mixes containing peat, and filter the air coming into your room if its ventilated. Hanging yellow and blue sticky traps is also good for monitoring purposes.
Microbes and enzymes will also help take care of any dead root hairs removing attractive food sources for the gnats too.
Another thing, frequency of irrigation isnt everything. One of the most out of control infestations I've ever had with fungas gnats was using
promix getting watered about twice a week.