PDA

View Full Version : How do overflows work?


augustscl
06/07/2011, 12:25 PM
From what I understand inside the overflows
are two holes pre-drilled in the tank. One hole is used to flow into
the sump and one hole is used for the return. I attached a diagram
that shows what I am talking about? Is that the way that it works? If
so, since the holes are so close together what is to prevent the
returned water from being sent right back into the sump?

My concern is that it only keeps cycling the same water and that it
doesn't cycle the water in the middle of the tank.

Thanks!

disc1
06/07/2011, 12:28 PM
There should be a pipe that the water comes back into and some lock-line or something so it goes back into the tank. There's more to it than just the hole. There's some plumbing involved. The water comes up the return and goes to wherever in the tank you have the plumbing pointed. Water from the tank flows back into the overflow and down to the sump.

pmrossetti
06/07/2011, 12:36 PM
From what I understand inside the overflows
are two holes pre-drilled in the tank. One hole is used to flow into
the sump and one hole is used for the return. I attached a diagram
that shows what I am talking about? Is that the way that it works? If
so, since the holes are so close together what is to prevent the
returned water from being sent right back into the sump?

My concern is that it only keeps cycling the same water and that it
doesn't cycle the water in the middle of the tank.

Thanks!

additional circulation in the tank prevents that.

augustscl
06/07/2011, 12:40 PM
Most pre-drilled tanks though have the two holes one for intake and return just inches apart. If the intake to sump is just inches away from the return though it would seem that a lot of the water that is being returned to the tank would come back into the tank

Take the attached image from an aqueon pre-drilled tank. There is two pipes coming up from the pre-drilled holes. One intake one return.

Which factors prevent that water from just being sent back down to the sump?

augustscl
06/07/2011, 12:42 PM
additional circulation in the tank prevents that.

So you mean to add a power head by the water return to help push the water back towards the center of the tank?

jeff@zina.com
06/07/2011, 12:43 PM
Most pre-drilled tanks though have the two holes one for intake and return just inches apart.
The holes are inches apart. The plumbing from those holes doesn't need to be. Pipe the return to flow away from the overflow.

Jeff

disc1
06/07/2011, 01:18 PM
In that picture the story doesn't stop at the top of the white pipe in the return. There is some lock-line (you can't really see it) that goes from the end of that pipe out into the tank and probably splits off into several outlets. So even though the holes are inches apart, where the water comes out and where the water goes back down are not anywhere near each other.

pmrossetti
06/07/2011, 01:20 PM
So you mean to add a power head by the water return to help push the water back towards the center of the tank?

put the powerheads anywhere you want. the circulation will get water to the overflow.

jerpa
06/07/2011, 03:02 PM
Your return line will end outside the overflow box so you will be pumping into the main section of the tank. The drain is located inside the overflow and draws its water from there so it will not be pulling water directly from the return to the drain.

saltydogs
06/07/2011, 04:46 PM
power heads move the water through out the tank