Not a water expert but it doesn't make sense to me to ro water that has been run through a water softener. Your outside hose water lines are not or should not be water softener water because of the salts if you water outside grass and the salts in the water softener. If i make any sense. Might want to to tap into the line before it gets to the water softener or figure it out. Your water line comes into the house at one point follow the line figure it out. You said that you live in a new place that has well water. I would get on that pronto amigo.
Whats gunna happen is when your ro membrane gets old it gunna leak all that salty water softener water into your ro water reservoir. Might be leaking it now. Might be a good time to check your ppms of your well water of your soft water water and your ro water and see what they all are.
Your plant looks nice, it sounds like you have grown before and know what your doing. Yes the plant should be back under the t-5s and the slow growth may be from light shock if you dumped that 400 right on top of it and freaked it out.
Not a water expert but it doesnt make sense to me to ro water that has been run through a water softener. Your outside hose water lines are not or should not be water softner water because of the salts if you water outside grass and the salts in the water softener. If i make any sense. Might want to to tap into the line before it gets to the water softener or figure it out. Your water line comes into the house at one point follow the line figure it out. You said that you live in a new place that has well water. I would get on that pronto amigo.
I copied my first part so I can say I told you twice. Dont be r.o.ing soft water, water.