API Root Tabs (10 Pack)API Root Tabs feed rooted aquarium plants directly at the source — tablets you bury in the substrate that release iron, potassium, and essential nutrients right into the root zone. They're the answer for heavy root-feeders like Amazon swords, Cryptocoryne, and larger stem plants, especially in inert gravel or sand that holds no nutrients of its own.Good to Know: Root tabs complement liquid fertilizers rather than replacing them: tabs feed the roots from below while a water-column fert feeds the leaves. Because the nutrients are released down in the substrate, they target your plants more than the open water, which helps avoid feeding algae. This is the 10-tab pack.How to Use: Push one tab into the substrate near the roots of heavy feeders (a common guide is one tab every few inches), about halfway down into the bed. Replace every few months, or when plant growth signals they're spent.