Let's look carefully at your watering method. Your plants have all the signs that the lower roots are shut down because they have been under water for too long. Your plant is dying... it is drowning.
Take some time to play with the moisture setting of that 3way meter. Forget the soil pH for now, you totally do not understand the concept of soil pH... that is for another time, and I don't think it has anything to do with your problem.
Use the moisture setting and slowly push your probes into the soil, first 3" deep, like if you had put your finger in to see if it was time to water. Push it in another inch and look what happens... it gets a little wetter. Keep pushing it down until that meter pegs all the way to the right, indicating WET. Raise it up and down a few times until you can determine how deep this water table is on the inside of that container. There is a lake down there, that you have never let go down all the way to the bottom. The top of that lake acts like a diaphragm to pull oxygen deep down into the soil from the top and in cloth grow bags, the sides. Those big feeder roots at the bottom have to get oxygen periodically, or their natural reaction is to protect the plant from the flood until it goes away. Your plant is going into an almost hibernation mode at the moment, trying to survive that constant stagnant water in the bottom of your container.
You should not water again until your moisture probe can show you that the water table has dropped down to the last inch of that container. That region at the bottom never dries out because of capillary action between the roots and the bottom of the container, but if you wait till you can see that the water is down to that last inch, you can be assured that your roots have gotten oxygen on that watering cycle. In veg, forcing the plant through a clear wet/dry cycle builds up the roots as they strengthen on each cycle because they are trying to find all the water. In flower, where to tend to try to push water at the plants and never let them dry out, I have realized about every 4th watering I want them to dry out too, all the way to the bottom, just to reenergize the roots with a good hit of oxygen.
You have seen it referenced in other people's signatures, I am sure, but please ready my How to Properly Water article. We can save your plant, but you need to let her dry out now.
