hey there, you have two problems and loads of symptoms. First off the fungus gnats, these are coming because your soil is moist, so what you really need to do is wait one day maybe two days more between waterings, the dry soil will dry out the fungus gnat eggs. Second thing you can do is to add beneficial bacteria, it works and it's organic and bio, you're looking at bauveria bassiana , bacilus subtilis or bacilus thurengiensis (how do you spell that?), these will attack the larvae, eggs, and adults. So organic will work better than anything synthetic in my experience. Second thing is that you added the booster, the booster is a chelation agent, chelation agents break down soil molecules into nutrient molecules for the plant. So actually it's not why your plant is showing deficiencies. So what's actually happening is that your light schedule is too hard for the plant , so the plant is using more magnesium. You need to do two things, add cal mag (keep the boost going!) to your feed and reduce your light schedule to less than 18hours until the problem stops spreading. Do this and the plant should fully recover within ten days. Hope this helps ! 🚀