I agree...

I make all my reservoir/air traps myself.
Something to keep in mind though is that the higher the water flow is thru your system, the larger the reservoir should be. To be effective at removing air bubbles, the water velocity has to slow way down so they can escape to the surface. The larger volume decreases velocity as the water passes thru the trap.
This is one reason I believe a lot of people have problems with the small commercial reservoirs like the Danger Den unit and bay reservoir.
Just my $.02 worth, good luck.