My plant seem to be stunned

this course of action is extreme relative to anythign that might be going wrong. looks generally healthy. what have you changed lately? drastic increase in light, by chance? all i can do is guess given the info presented here. just go with water only irrigation for a bit and then go back to a fertilizer plan. how concentrated you make it will determine how often you apply it. every other? every third? soil has numerous "right" ways to do it. one thing.. i see hints of bad irrigation methods. So, stick to something simple. When you irrigate, make sure entire thing gets wet. then, wait for top 1" to dry before repeating that process. if you re-irrigate at same loss of weight, then it will require the same volume of water. do not choose a volume to give out of the ether. that will lead to problems. that's the wrong way to do it. the pot size, substrate components and the amount of time you wait as the plant drinks it up is what determines the volume needed. use more perlite. your root zone may be too wet and slowing growth down. regardless you'll have a more optimal rootzone if the ratio of soil to perlite (or similar) is 1:1 so if your watering habits are drastically different than that, i'd get that in line first before making any other drastic changes. custom diy light ? if you made a high end light, over 18 hours it's easy to give too much. look up dli, and guesstimate.. wehther over 12 hours or 18 with ambient co2 you don't want to be over 35-40 dli... to dial it in you'll have to observe and react, but that's a solid ballpark maximum.