Active Aqua Air Stone, Case of 12

I currently have 3 kinds of airstones. these being my middle priced ones. I have to say the cheaper round ones work slightly better then these, despite having less surface area. these are less porous then my cheaper ones and when set up on the same pump you can clearly see the cheaper one is diffusing more air. Im sure if you only used these on your system it would work fine, but I would imagine that because there less porous it would put more back pressure/ strain onthe pump. (not enough to really affect the pump)