gnats are easy... mosquito dunks/ BTK, aquabac, or nemitodes...israeli genus.. add which ever product to your water and soak... SM90 is ok as well.. you can spray adults with it to disolve there lil bodies..
natural approach is 2" layer od playgroud sand.. and bottom feed to let top dry off.. killing larva.. its slow but does reduce populations by 80% in first week.. but its slow... going...
diatomesiuos earth.. is crushed up fossils, it looks like salt and is sharp pices of fossil that cuts larva bodies... you top dress your post with DIATOMASIUOS EARTH.. ALSO NEED TO bottom feed..
mites... florimite or
avid... one shot in veg only... it trully is a one true killer of the mite and eggs which means its an ovacide.. florimite is good for 20 days with one spray . I still do extra sprays.. but I prefer to only spray in veg cycle or on mothers... it does not wreck the plants foliage at all. not even a curled leaf any where... I even dip questionable clones in florimite.. as a safty measure..
I dont even bother with NEEM or end all or phrytuim based products.. the later just distroys the foliage like nothing else, its sad really.. your basicly killing your plant to try and kill mites.. its like chemotheropy using safers end all or other phyrthium based leaf sprays.. I hate that shit..
montray garden spray is usually only good for thrips specifically.. but is effected to lesser degree on other pests.. but it nukes thrips which other product wont even effect thrips in the least.. also monteray garden spray has an active ingredient called
SPINOSAD.. its OMRI .. and very safe but gets a bad rap due to its BEE killing capacity... people love bees and wee need everyone..
you can buy
SPINOSAD in a agri grade concentration called CONSERVE SC or semi professional grade called NATURALYTE.. sell it on ebay.. stuff is lightning fast and also does ZERO platn damage....
also get a hanging pest strip... cant recall the name.. but there about 6" long 2" wide.. yellow flat bar about 1/4" thick like soap.. incased in a white plastic hanging case with a hook... these really work great to add extra measure of protection.. might be called NO PEST STRIPS .. YES Ortho Home DefenceMax
No Pest Strip, OR HOT SHOT NO PEST STRIPS..
ALSO you can try a really easy method thats cheap and works..
50/50 water and iso alcohol.. in a spray bottle... works on mites and gnats . spray plants but only VEGGING PLANTS... the mixture will disolve tricombes on your buds... so not a bloom options...
also dont neem blooming plants.. taste like crap...
well thast a bit for you.. good luck