The layout of our korrel beds is horizontal, rather than vertical as Mediamatic's tower systems. When using one pump and one timer, the amount of water filling all the beds must be at exactly the same rate, otherwise there is a risk of some beds sitting half full and drowning the plant roots, when the pump turns off.
Each 'leg' is exactly the same length and diameter of vinyl tubing.
Sizing them identical was the only way to deliver water in synch to all the beds.
It took several failed attempts to arrive at this solution. Live and learn!