Determining the weight of 100 CDs depends on whether only the CDs are weighed or if the CDs have sleeves or jewel cases. A single CD by itself weighs about 0.58 ounces. Therefore, 100 CDs by themselves weigh 58 ounces.
Nitrogen is essential for the growth of leaves and stems, and it helps to give plants a rich, green color. If it is lacking, plants will be pale and sickly-looking, and the oldest leaves will look worse than the newer ones.
Plants will absorb ammonia and nitrate. Planting a tank with very low <10 ppm of nitrate would not come out too well if the plants are fast growing. These are both nitrogen fertilizers, and one of the macro nutrients needed by plants. Lack of nitrogen usually leads to pale, almost white plants.