A length of acrylic (or pvc for portable water) tube - ~ 1/2" to 3/4" ID, (rigid is best, but some have use semi-flexible).
A connector from your acrylic tube to your filter output tubing - best to find one with a barbed end (for your filter tubing) and the other end a slip joint that fits exactly over your acrylic tube.
A cap for the acrylic tube.
Drill holes in the acrylic tube, cap one end, and connect the other end to your filter using the barb/slip connector. <Some people add plastic lawn irrigation nipples to each hole so they can individually adjust/ direct the flow from each hole ... I think that is overkill.>