I also think your fine but you could add a metal gang control valve. I used this when i had a wall and i like the way i could control the speed of the bubbles!!!View attachment 156250
That seems too be enough. My fish keep swimming through it and my polleni like attacks the bubbles it's entertaining.
Agreed, how many outlets/airlines have you running from the airpump??That's a good idea but I've also heard its not a good idea to restrict the air flow in any kind of way?
Well if you go back to the two lines, feed them into the 4gang valve, one line each end. Then if you need to reduce the power going to the airstone, simply open one of the valves that is not being used. Like a pressure release, this way the pump is not being restricted. Hope this makes sense and is just an option you could look at. Worked for me at the time....It has 2 outlets but I made a line so that they both can feed too one line. I think I may use that or one airstone 2 seems like too much