I'll just expand on my problem with the ATO. I switched off the Return Pump because I wanted to disconnect it so I could have a look at the return flexi pipe connection, and then figure out what I had to do to connect the Vectra. While manhandling the return pump to disconnect it I managed to knock the ATO resulting in the floating part snapping off! As always, while trying to fix one thing you make a mistake which results in something else needing fixing. As you can imagine there was a lot of bad language used. I did go to the local hardware shop to try and buy another but apparently they are 'too old' and the store doesn't stock them. I had to order a Red Sea replacement kit from my favourite online store.
One of the problems here in Germany is with the sizing. Believe it or not the vast majority of plumbing stuff comes in Imperial sizes. I think this is because after WWII and the re-build, most of the help came from the US or the UK, and the Imperial measurements for plumbing has stuck. However, there is an awful lot of stuff that uses Metric as well, so it's a real mish-mash of sizes! You would have thought that there would be loads of converters/connectors between the sizes but this isn't the case.
I am still trying to find out the size of the flexi return pipe on the S-650! I've put the question to Red Sea Support so I'm hoping they will come back with an answer soon. It's the internal size of the pipe that I really need.