Hi, I'm having a problem. My plants have been dying off. First, they turn yellow between the veins and then the tips of the leaves will turn brown and die. After that, the rest of the plant dies. They also seem to be stunted, they won't grow. I was watering my plants with tap water. I know that I'm not supposed to, but I didn't have an option at the time. I know that the city adds phosphorus to the water, which CAN cause phosphorus toxiciy, which can lead to iron and zinc deficiencies. Well, I bought some more distilled water and changed the soil, but the plants continue to die. This is the first time I've had a problem like this. I used to grow on a table in the middle of a room with a light right above the plants. This worked well, but I thought it would be better if I had a set up that would condense the light more. So I bought 2 grow boxes. Now I don't know if the plants are dying because of all the phosphorus or if it's the boxes for some reason. The boxes are 2.5'x4.5'x6.5'. On the inside of the boxes they are lined with white vinyl, or whatever that reflective white material is, and the outsides are heavy black canvas. So does anyone think it could be the boxes or the remaining phosphorus left in the plants? By the way, everything else is fine. Soil ph, temp, air flow, humidity, you name it.