is ur house using GI pipe ? those pipes get rusty inside over the years, so u need to clean the pipe as much as possible, or maybe u want to consider making new piping PVC type. No point getting a pump if u r using GI pipe cause it will get rusty inside n the pressure is low again in future. For rain shower u need to have a good water pressure for it to spray properly cause it has many holes.

GI pipe is like those metal pipe, they r smooth inside when new , but when old it becomes rough like cancer





PVC is plastic n in Malaysia we normally use the grey color ones, they r smooth inside n last long but cant stand extreme high heat