I built and used this successfully on Friday. For once the kitchen wasn't like a scene from the Titanic.
https://farm8.staticflickr.com/7309/13834710923_90bc18b558_c.jpg
That's a Whale 12vdc High Flow Pump - bought from GoOutdoors in Granton for £34.99, its for caravan use and passes easily through the neck of a 25L container. It's output is 15L/min and operates at 3.8A. The power supply is a 12v 5000mA unit from Maplin, about £35. A quick fit power connector to connect the PSU to pump was about £3. The optional box and push to hold switch were also bought from Maplin and combined came to about £12. The rigid pipe gubbins is push fit stuff from B&Q can't remember how much it was but you could use anything, I was just trying to make a hands free tank hanger, the green hose is 12/16mm JBL hose from Fishkeeper. The filter guard I had laying around.
15L/min is overkill for my tank, that's a water change in under a minute. Its not a variable flow pump but there are lower powered versions. I belts and braced it and got quite a bit more than I was expecting, the £25 pump would easily do the job. There is a caveat to the pumps in that they must not be used beyond 15mins worth of operation at any one time. When I put this together initially I used a 1A 12v supply (nothing in instructions telling you what power requirements are other than its 12v and a 5A fused plug) the pump operated but was not able to maintain a head height beyond the neck of the container and pumped slowly like a peristaltic pump. I knew something was a miss so i did a search for faults with the pump and after a while discovered the always buried manufacturer operating stats PDF that said its 3.8A 15L/min. You would think something important like that would be in the instructions, but hey ho, were not all natural sparkies.
I did the Eheim (2000) route and got sick of having to manually lift water into the bucket first to do direct filling. The alternative was the pain in trying to get a siphon going from the 25L container through the Eheim resulting in lots of swearing and a recreation from a scene from the Titanic. Tried rigging up a spare canister filter to try do the job, but that was just more frustration.
For me this was the preferred DIY solution for those that hate to lift water and don't fill direct from the tap. The push to hold button is my dead mans switch so I can't cause a flood by getting in kerfuffle reaching for an off switch which I have done in the past. I can now sit and enjoy the Storm Function on the Aquaray controller than actually be the storm myself.