OK, thanks for the reply!
so you have the top of the spraybar just under waterlevel? I assume the further you move it down the less bubbles you get? Should I be getting just a few bubbles then, barely noticeable? I'm getting quite a lot now, if you get close to the tank they look awful!
I'd have to lengthen the pipe going to the spraybar if I was to mount it vertically (for physical reasons), and you're meant to have the input and output pipes approx the same length aren't you? They wouldn't be if I did this, the output would be quite a bit longer. Would taking the pipe from the right of my tank to the left, then securing the spraybar at the other side (the left hand side) vertically, be a problem? Would there still be enough power in the water left for it to shoot out of the spray bar as normal, even though it'd be going up, across, then down?