Planted Tank Guru
Join Date: Jul 2010
Location: British Columbia, Canada
They can be placed singularly, or in pieces, near larger plant roots, or interspersed wholly or in pieces, near and among several plants or a grouping of plants.
Depending on the thickness layer of your substrate, you should try to place them at a depth where the nutrition from the tabs can most easily be accessed by the approximate bottom level of the plant roots. That is generally at near a 1" to 2" level for many plants.