To make a sump, what kind of pump would I need? Would water feature pumps work? Also, what are the advantages of using a sump instead of a canister filter?

Yeah, a good sized pond pump will work. Advantage is MUCH more media space and MUCH more water volume and it gets gear out of the main tank.

sumps hide all the heaters etc .. (more space in tank ) , also more media can be added

Is it possible to have a sump that does not need a pipe drilled into the side of the tank? I dont really want to mess around with drilling.

Are you building the tank yourself? Usually drilling the hole and making an overflow doesn't cost much more.

Yes. There are many, or most that have the hole drilled into the bottom of the tank.

Or you can use a HOB overflow, but they're not the preferred method, much less reliable.

IMO "messing around with drilling" is far easire than messing around cleaning canister filters! I don't know why anyone would use anything other than a sump for any big tank.

An external overflow box can be used if you do not want to drill your tank. I'm not sure what the costs will be but heres the LINK to Melevs reef site which tells you how to make it. Also here's the LINK to get it started. Hope this all helps.

Well, for one, the tank is already set up so I don't really want to drill anything in.

Anyways, I have a choice between using a canister or a sump and I would much prefer the sump as it comes up to be cheaper than the canister, because I have some of the required parts to make the sump (spare tank, pipes etc).

I was thinking of using a pipe as a vacuum and allowing gravity to do all the work while the pump pulls up water to the tank. The only downside I see is that if the power goes off I'll need to reset the pipe.

Suggestions?

That external overflow (weir) restarts itself when the power goes out. You can see it running here.

From my understanding, as long as it stays primed, it will autostart itself when the return pump kicks back in.

Yes, I was about to post that I read through it and found it extremely useful!

However, does one have to make the weir himself or can he buy it?

I'm not 100% sure on that. But its worth emailing a petshop about it. And if it isn't readily available here, this could be a business opportunity for a importer to jump on as I'm sure other people are going thru exactly what you are atm...

found one at deepblueaquarium.co.nz. here's the link to the page.

Whoa, $120 for a weir? For that price I might as well just buy a new tank and drill a hole in it.

Is it possible to actually make your own? Should make an interesting side project for the holidays.

more then possible. give one a go as mark explains each step really well in that guide.

Whoa, $120 for a weir? For that price I might as well just buy a new tank and drill a hole in it.

Yup! You could try make one, but unless you value your time at under $10/hour it may be 'cheaper' to buy one.

The only time I would use a weir is if I had an established tank that I didn't want to pull apart to set up with a sump. Most big tanks have bracing across the front/back which could make it difficult to use one.