15 Osmocote+ Size 00 Root Tabs
You are buying 15 Osmocote+ Size 00 root tabs. They must be buried in the substrate so they do not cause ammonia spikes. Depending on density of plants, 1 tab can fertilize a 4"x4" sqaure for 3-4 months. 1 order can easily fertilize an entire 10g tank for at least 3-4 months.