just putting the perspex on baking paper on an oven tray worked fine - it stays really bendy [and really hot] for ages after you take it from the oven - when you sit it on the PVC pipe [with a layer of baking paper in between] it wraps to the exact shape of the pipe. dont have a link for the design, i just made it up as i went
i moulded the perspex on the outside of the pipe, then installed it inside the pipe - as it is more than 180 degrees, it kinda pushes itself into place quite well - i only had to silicon it to seal it, not to hold it in place.
its 500 high, 100mm PVC pipe.
2x endcaps
perspex is 3mm, approx 350x250
1xhansen 15mm tank fitting
1x25mm tank fitting
some elbows, and some 15mm pipe.
inside the reactor, i attached a kind of shower head thingee to the 15mm pipe so the media doesnt siphon back up the pipe and into the impellor if the power goes off.