Help!!!

I have been told that I am over watering and they are wilting. I bought a moisture tester today. I put the sensor in the soil to the bottom and middle and top. all readings are dry dry dry. The plants are wilting more. Here is what has changed since they were recovering from Nute burn. I took them off of 20w 2 ft flor. and on to a 150w HPS I put a small fan in the room and have it pointed to the side so the breeze is not direct. They are wilting fast. Something is taking its toll on them. The soil was plane potting soil from Wal-Mart. No nutes pre put into the soil. They were doing so nice well until a few days ago. I moved the light up a bit as it seems that something I have done is not doing well.

are those two plants in one container?

Yes there was one seed that did not look like it was going to do well and they both came in. I can not seperate them now. Unless I cut it and try to clone the whole plant.

over watering and under watering look the same is there a catch tray under your terracotta pot holding water after watering your plants?

what is the room temperature at?

There was a catch tray and I would empty it out after the drainage was done. The temp runs about 72 to 78. One thing that has changed is the light. I put a light meter under the 20w floresence and it regested 300 to 400. I put the meter under the new HPS light at the plant level and it regesters 1000 plus. When I went out side in overcast light, it would regester 4 to 500. Thats twice the light that it would get if it were outside in the day. I would bet it is light shock.
I also repoted it. The roots were trying to find deeper soil when I pulled it out of the teracotta pot. The new pot is twice the size and I put potting soil with vermiculite and sand to fill around the plant. I did not disturbe it much repoting it. I really do not want to loose it.

Well I have done some research, and others have had the same problem. Plants that are not used to HPS and have been under FLOR. can wilt. Just as they can wilt if grown inside and then taken out side. I hope they recover. I also raised the light about 4 feet above the plants. The meter now shows 500 to 600 at plant level. A bit over what the flor. reads.