Make feeding easy to inspect
A shallow glass or ceramic dish keeps sinking food in one place and helps you see whether the colony is eating it. Place it where shrimp can reach it and where you can retrieve it.
Observe how much is consumed over the feeding period. Colony size, available biofilm, and food type affect how quickly a portion disappears.
Clean up without stripping the tank
Use a pipette or narrow siphon to remove leftovers and the debris around them. Avoid vacuuming every surface where shrimp graze.
If food repeatedly remains, offer less next time. Overfeeding is easier to correct by reducing portions than by repeatedly cleaning a mature aquarium bare.
For your own tank
Use the same observation window for a few feedings so you can compare portions fairly. Shrimp may graze elsewhere and ignore a pellet when natural food is available. Remove leftovers gently, then reduce or space out the next serving if waste remains.
Use these as general hobby references. Test your aquarium and confirm product guidance before making changes.