Equipment List

Did you look at DC return pumps?

I hadn't as this is my first sump.  I was only looking at what I know to be good brands.  I'll have a look now.

@marquismirage
I have a Jecod DCS12000 but I have seen Jabao and Jecod used interchangeably, same with the DCS12000/DCT12000. I was never able to discover the differences and for sure they will be a copy of one of the early expensive German DC designs, but they certainly work well. Mine is running at 5000l/hr and is almost completely silent, even with the cabinet doors open.
It has the feed button that shuts it down for 10minutes, @Sue I don't tend to shut down to feed but I can definitely see the advantage after your experience.

It seems to be impossible to search for DC pumps without getting the majority of hits being for them. I have since seen that TMC have a DC pump, it will no doubt be Chinese, but if you want a recognised name on it you could look at that as well.
I tested mine in a water butt when I received it as I was building up the parts gradually, under 3foot of water it still produced a jet of water 6" above the surface. Stupidly I had tried it in a 30litre bucket before that, but it flung all the water out in a plume and soaked me before it got anywhere near full speed

As with filters the pump is the one really critical moving part, if you can get a spare ....just in case. I had an external filter spring a leak once, and it really concentrates the mind if you know you HAVE to be able to fix it.