They are generally used for heavy root feeder plants, but all can benefit from it if there is no other dosed ferts.
What exactly are you trying to use (brand, ingredients and %)?
The copper contained in the ferts are generally low enough concentrations that they won't harm inverts. There are plenty of people who use similar copper containing products (nutrient enriched substrate, root tabs, even CSM+B fert and most don't report any issues with their shrimp that still healthily multiply in their tanks.
Copper is even in some fish/shrimp food. Inverts actually need some copper (very little) for Hemocyanin (essentially to breathe, like Humans' Hemoglobin).
You want to try and put the root tabs deep enough so they don't pop out of the substrate and release faster into the water column (overdose). Most of the nutrients from the root tabs stay within the substrate, but some still dose seep out and can feed the water column (just a small amount though, I guess the more "loose/aerated" substrate can leech more/faster)
API Leaf Zone for leaves and I just put a single tablet in an area with lots of plants of:
Tetra Pond LilyGro
Derived from ammonium phosphate, potassium nitrate, urea formaldehyde, manganese sulfate, ferric sulfate, zinc sulfate, copper sulfate, boric acid, sodium molybdate.
Total Nitrogen (N), 10%
Ammoniacal Nitrogen, 5.5%
Nitrate Nitrogen, 2.4%
Water Soluble Nitrogen, 1.5%
Urea Nitrogen, 0.6%
Available Phosphate (P2O5), 14%
Soluble Potash K2O, 8%
Boron (B), 0.02%
Copper (Cu), 0.05%
Water Soluble Copper (Cu), 0.05%
Iron (Fe), 0.11%
Water Soluble Iron (Fe), 0.11%
Manganese (Mn), 0.12%
Water Soluble Manganese (Mn), 0.12%
Molybdenum (Mo), 0.0006%
Zinc (Zn), 0.07%
Water Soluble Zinc (Zn), 0.07%
The Leafzone I guess is used up in a week but the Tablet say they will last a month.
I have eco-complete so I am hoping the tabs will like enhance the eco-complete which already has minerals in it. However I don't know how long it last.
My plants are:
Java Fern "Narrow"
Moss Ball Mario
Dwarf Baby Tears
Golden Jenny Lysimachia Nummularia
Ammannia[censored] reineckii 'Pink' roseafolia or gracilis
Argentine Sword Echinodorus[censored]argentinensis
Betta plant Cryptocoryne Wendtii Green
Anacharis Bunch Egeria Densa
Moneywort Bacopa monnieri