redsea doser

Hi everyone, I’m setting up a Red Sea doser with the RedSea colored dosing lines. What is the best/simplest way to make sure the dosing lines go to the bottom of the containers? I have tried to set the container with a 1/4” bulkhead and rigid tubing but i can’t connect that to the RedSea doser...

I have a 3 month old redsea doser that I used for 1 month. Then when to trident control dosing. I will be pulling it off control board tomorrow. It will come with plenty of redsea dosing lines. Still have box and paperwork for doser Asking 350.00 shipped Can send more pictures if needed...