i know this is probably not an advanced technique but couldn’t figure out which one i should choose so i picked what sounded best lol. so i’ve had these ac infinity auto pots that i’ve solely used for catching my runoff this grow but ive developed a severe gnat infestation so ive started bottom watering with the auto pots to try and get rid these bastards. my question is since i’m using powdered nutes(top dressing) how should i go about doing this? i’ve considered just watering normally when top dressing and bottom watering in between but would this prevent the plant from taking up all the nutrients im giving her? since the powdered nutes break down over time should i just go back to liquid nutes for the time being? any advice or suggestions are greatly appreciated! tia
I don’t see any other way, if you are top dressing, you need to top water in order to get the plant to uptake the nutriments.
The classic ‘holy trinity’ for gnats Diatomaceous Earth (only works when dry), Mosquito Dunks (BTi), and yellow sticky paper.
Another item worth mentioning is a small fan. I have a little USB fan sitting on the floor of my tent. The number of gnat corpses around it is worthy of note. 
Sand is another option. You want the white sand blasting sand (quartz).
In your situation I would top water the nutes in along with a good dose of BTi in the water. Once you think you’ve got the nutes down into the root zone switch back to bottom watering, let the top dry out and top dress with the DE.
The bonus is DE is also a slow release source of silica.
Cheers
G
im dealing with gnats rn also. subirrigation pots with living soil. same conundrum. topdress slow release organic ferts.
i basically just water in the ferts with just enuf top watering to mix them into the soil. i sometimes let the res run dry but sometimes dont bother.
bti has given mixed results…experimenting now with a mesh barrier over the pot. next will be beneficial nematodes. good luck with it.
They seem to like bowls with a thin sticky layer of sugar water, kind of like the yellow stickies. Left a coffee cup in the grow room one day with a tiny bit of coffee/sugar left in it. It evaporated, and there were a bunch of gnat corpses stuck to it.
There was a bit of a learning curve for me when i started using BT.
I’ll presoak the bits for 24hrs for full activation. you also gotta apply regularly for at least 2 weeks, or longer than the life cycle of a fungus gnat as it only affects the larvae. If you dont apply long enough, some will survive and be able to reproduce.
Recently got rid of a decent amount of gnats with just mosquito dunks
I normally water two times after I top dress. Then I bottom water. I still have gnats tho.
Last time i got rid of them, i used a dunk every other watering if i recall. Ill reuse them a couple times but ill keep them soaking the entire process so sometimes theyre soaking 48-72 hours
Also gotta treat all your soil at once, even stuff not in use or you might miss some larvae
Even when i go hard for 3 weeks w the mozzie bits sometimes its hit or miss. Ithink they might work better in regular pots but my sip pots have a overflow hole they can access the soil from and its caused issues to have the bti tea sutting in the reservoir and lines.
Liquid BTi is the move. Much more potent than the bits. My earthboxes were getting really bad with gnats and it flattened them in a little under a week. Now I just use a couple drops every time I fill the reseviors and they haven’t returned. The brand I use is Microbe lift.
thank you everyone 
going to check out some of the things commonly mentioned and put a end to these little spawns of satan lol
Just crush about 1/16th of a Mosquito Dunk in to the top of your pots and scratch it in the top couple inches. You can get yellow 4x8 sticky traps from Amazon for pretty cheap and put one in each pot. An oscillating fan down low will also help keep them from landing in your pots and constantly disturbs them.
Have bottom fed with Athena Pro (their powdered line) with excellent results quite a few times.
I’d suggest a simple two part like Jack’s or mega crop and dosing half to 2/3 the suggested until you get a feel for it. Good luck!