Merit 75 Max Dosage? Root aphid help

So I have had these bugs for months and tried 6-7 different organic pesticides including azamax, master garden pest oil, plant protector, SNS 203, Neem oil... Hundreds of dollars later Nothing has worked and the bugs seemed to only get stonger. I decreased the number of plants I had to a managable number and are all in veg.
I Started going systemic almost 2 weeks ago with Merit 75 it has put a large dent in the population and I haven't seen adult bugs since then but I can not get rid of the adolescents. I've treated 3 times including two nights ago and the bugs are still there and on some older plants they are there in force. Ive been using a fat half tsp. per 5 gallon of water every other watering.
I need help! What is the max dosage of Meritt 75 yall have tried without killing plants? I can not figure out what to do and these bugs are really screwing with me. Any body have any other advice besides moving to another systemic like a avid which I was trying to avoid originally and after using merit am definitely trying avoid

gunna try a few plants with a dose 2x. 1tsp per 5 gallon watering and see if the plants can take it... ill let u know

Yea Ive been running 2x merit 75 and the plants are still strong but so are the root aphids. The plants got slightly burnt with all the shit ive been drenching them with but are no worse for wear. Maybe 2-3 weeks or merit only killed all the large adults but the smaller pinheads are still in the dirt and after agitating the containers they generall migrate up the the soil rim. I am moving on to bayer complete insect killer with merit and hoping to smoke those mother fuckers. Also looking to get my hands on met 52 but is expensive and can only be incorporated when mixing the soil Ive beeen told so just to protect future generations not the ones I have vegging

Had a bad root aphid infestation and knocked them out cold with merit 75. I strongly encourage inspecting those little ones that are left. I tried and tried to kill them, only to find out, aphids were long gone and they were actually predator mites cleaning up the leftovers. I never purposeLy introduced the mites and not sure where they originated from. They were immune from the merit due to only feeding on the dead aphids. They slowly disappeared within first couple weeks of flower. Haven't seen any sign of a pest in over a year! Good luck

Does this kill stubborn fungus gnats and their larvae?