trying to build a sump?

You need some way to get the water out of the main tank to the sump, and it needs to be balanced with the water being pumped back to the display. That means either drilling the main tank or having an overflow box. I suppose you could have the sump above the main tank and pump water up to it.
 
Yep, I built it myself. Can you really fit a sump, refugium and baffles in a 10? It was quite a squeeze in a 20, but my skimmer's pretty big.

You can't quite do it like a canister filter, since it's an open system. With a canister, the water is pumped out, which pulls water from the tank.
 
Hey Dave, when I build the sump, I am really confused how the overflow tank is what gets the water circulating, I thought the pump does that. Can you please explain how does it work, this whole thing just seems really complex, building the sump seems easy, but hooking it up and getting it up and running and the whole overflow box thing confuses me?!?!?!?! :eek:
 
Like so many things, it's easy once you see it in action.

Water overflows either through a drilled hole in the tank or an overflow box into a pipe that leads to the sump. A pump, either in the sump or plumbed to a hole drilled in the sump, pumps water back up to the main tank. The pump really drives the whole process, because there will be no water to go through the overflow if the pump doesn't move water from the sump to the display.

melev's description may be better:http://www.melevsreef.com/what_sump.html
 
Maybe this will help. Go to the bathroom, plug the sink, and turn on the water.

wait...

wait...

wait...

Eventually the sink will fill up, but won't overflow because there is a drain up near the top that prevents it from overflowing. That is exactly what an overflow does.

Now, imagine that the water flowing out of that drain is going to a sump, rather than going to the sewer, and is being pumped back to the sink. The sink won't overflow because the drain keeps it from doing so. The sump won't overflow, because only the water above the level of the overflow/drain goes down there.

Any better?
 
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