Shrimp produce little waste and help keep the tank clean so that may answer your question.
But I need to air my opinion here and feel obligated to do so.
To "only" add them to keep the tank clean is unfair.
I apologize in advance if I seem harsh and don't want to read too much into what you wrote; you may have been encouraged by someone, a salesperson perhaps, to get them for that reason---but shrimp (and snails) are not janitors and definitely don't replace us as far as maintaining the tank.
We are responsible for tank maintainence.
They are awesome in their own right and you will find that out if you get some.
Huge personality and intelligent creatures. I was surprised!
View attachment 119891Before long you might even start a colony in their own tank...they are quite addictive
View attachment 119889
If you start a colony you will have to get them their own food ...algae wafers, yum.
Also, if you plan to breed egg-scattering fish in the tank the shrimp may reduce the number of eggs as they snack on them. Likewise, fish often hang around a female shrimp as she is releasing her shrimplets for the same reason.
Keep us posted!