To answer your first question, yes it is bad when you move your plants in and out all the time. Your plants want to have a steady light source and environment that isn't changing all the time. Every time you move them back and forth, it stresses them out as they try to adjust to the new environment. Then once they are just getting used to one you move them into another environment. While this is probably not causing the brown spots and curling leaves, your plants definitely don't like it.
You should pick either inside or outside and leave them in the same place all the time. If you want maximum growth, definitely go with outside. Even though they won't have 24 hour lighting, they will have THE SUN which is so much better than the lights you are using indoors. The sunlight is also free.
Another bad thing about moving them inside and outside is that you are pretty much guaranteed to get spider mites that way. If you don't already know, spider mites are the most horrible, hard to get rid of bug that you could possibly get on your plants. If you keep the plant outside the mites will usually try to move on to other plants that are not so hard for them to feed on. Cannabis is tough and resiny and they don't like it if they have a choice. That said, if you bring them in the house and they have nothing else to feed on, they will invade and eventually destroy your plant. You can tell if you have spider mites by looking at your big fan leaves. There will be tiny white dots on the top of the leaf that come from where the mite sucked the juices out of that spot. On the undersides of the leaves you may be able to see adult mites, they are just small specks and look kind of like moving pepper. If your plants are heavily infested, you might find webs that the mites have made, which are full of more mite eggs.
