You think they are spider mites? You're in for a BIIIIG fight. I'd stop spraying your plants with the alcohol and stick to stuff made specifically for plants.

I would also put them back on your nute solution......but in half strength for a few days. Keep an eye....again.....on trends.....does the ph seem to be getting better, worse, same?

When you're plants are stressed or something is going on that you are not sure of......my best advice would be to pull back your lights and drop your nute level by aboutr 1/3 to 1/2 until you can figure the issue out. Too many big changes....today water....tomorrow back to nutes and back and forth......will stress the plants out by itself.