How to solve the problem of more than 10 meters RGB lighting failure?

There is no lighting decay phenomenon when you connect 5 meter RGB led strip light:

There are obviously lighting decay phenomenon when you connect(series connection) 10 meters RGB led strip light:

The way to solve the lighting decay: you need to use a RGB LED Strip Amplifier when you connnect another 5 meters RGB led strip(If you want to connect 10 meters, you can use 1pcs RGB LED Strip Amplifier;connect 15 meters,use 2pcs RGB LED Strip Amplifiers), like the following picture shows:

The installation of power supply and RGB led controller:

Use a DC cable to connect the V+ V- of the power supply AC input, connect the power cord(US/UK/AU/EU) with the DC cable. And use another cable line to connect the DC output of the power supply and the DC input of led controller. And then you can use a RGB LED connector to connect the DC output of led controller and RGB led strip lights you have.

The installation of RGB led Strip Amplifiers and RGB led strip lights: 

Connect the input of the RGB led Strip Amplifier and RGB led strip light, at the same time you need to use another power supply to connect the led strip amplifier. If you want to connect more led strip lights, you can choose LED Splitter to connect.