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.
Plants and animals need nitrogen in order to make proteins. Proteins are essential compounds for healthy growth and fully functioning organisms. However, nitrogen is often in short supply to plants in both natural and agricultural systems. If nitrogen supply limits the growth of plants then the animals which feed on the plants will also suffer.
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.