I use the Aquaforest Components Pro 5L containers as my dosing containers. They are white and a good size.
Till now I’ve taken a low-fi approach and simply drilled a hole in the caps and run the dosing tube into the container. This doesn’t always work well (the tube may not reach to the bottom or sit curled up and block flow).
While on holidays I’ve took the opportunity to make some DIY lids
