Nonbuilt-in overflows

[krustytheclownfish]

Thinking about adding a sump and just wondering what people use that don't have a built-in overflow? Do you use one the hangs inside and outside the tank and has a siphon between the two or just a hose the siphons the water down to the sump or something else?
Also, how do you change water in a tank that has a sump without losing the pressure in the siphon hose? Is there a way to just turn off the return pump and do your thing and then turn back on the pump and have everything working like before?

 

[mr . salty]

You MUST use an overflow box.Just a syphon hose will compleatly drain your tank if your power or pump ever fails.A properly installed,GOOD overfow box will avoid this mess/flood.And also should keep the syphon till the power comes back on.Water changes are easily done by just unplugging the return pump.then when you are done just plug it back in.

 

[option720]

Krusty-
I'm also looking into to adding a overflow, and from what i have seen you want one that will pull the surface water down to the sump as well. These overflows usually have several notches that allow you to skim surface. ABSOLUTELY DO NOT just siphon water out of your tank.....it could suck you fish up too. Check out ozreef.orgainization ( lose the "ainization" if you know what i mean) , they have a bunch of DIY overflows that are pretty easy to do. hope this helps
Emile
[ June 19, 2001: Message edited by: option720 ]

 

[q]

CPR makes a good syphon set up and even comes with a prefilter. You can adjust your flow rate as well by adjusting the depth that the cahmber sits inside your tank.

 

[krustytheclownfish]

Mr. Salty- couldn't you just put a siphon hose say an inch or less in the tank with a screen over it? This way it would limit the amount of water that would get drained from a power failer into the sump and also protect the tank inhabitants from getting sucked up. Not saying it's the way to go, just wondering. Also, I'm still a little confused over why the siphon wouldn't keep siphoning when doing a water change even if the return pump was turned off and eventually, depending on how much water you take out, run itself dry and break the seal. Doesn't the siphon either have to keep siphoning or stop because the suction is broken...unless you have some type of valve to stop the water flow yet keep the suction? I'm probably just missing something, but just trying to figure this stuff out. Thanks.

 

[marine qa]

KrustytheClownFish,
A purpose of the ******** and exterior overflow boxes is to prevent the syphon from breaking after the pump is off. Both boxes retain their water despite the lack of new water and the u-tube that connects them never loses suction.

 

[krustytheclownfish]

Alright, maybe I'm just a dope, but I still can't see how having an overflow box inside and outside the tank will keep a seal on the siphon tube if the water level falls below a certain point. There isn't a pump on the siphon side right, just the pressure and gravity bringing the water into the inside box through the slots, through a u-tube to the outside box, and down through a tube to the sump? If that's true, then say I'm doing a water change and the water level falls below the slots of the ******** box. The water in that box would still continue to siphon through the u-tube(with no new water to take its spot, since the water level in the tank is below the slots) to the outside box until the inside box's water level falls below the u-tube and then the pressure would be lost, right?. Ok, what am I missing? Be patient, one of these days the light bulb will come on.

 

[mr . salty]

The key is that the drains holes inside the OUTSIDE box either are divided by a wall that keeps all the water from draining out,or there are tubes comming up from the bottom of the box to keep it from draining compleatly.The syphon tube is below this minimum water level,so it keeps water in the box at all times.Even if the pumps are off. Look at a picture,you will see.

 

[lcc]

I have heard a lot of bad stories about hang on overflows. Floods are the most common, and I believe that they tend to be rather noisy. I heard that they loose their suction and can cause problems. When I was shopping for my new system, everyone I talked to told me to get built in overflows, and stay away from the hang on types.

 

[broomer5]

No question that a built in overflow is superior to an external one.
For those of us using the hang on the back external ones ... here's the tip of the day.
One of the keys to preventing the siphon from losing it's prime is to insure that your return pump is strong enough, that it pumps enough water from your sump, back up to the tank to allow sufficient flow though the overflow and up/over the siphon U tube.
Small air bubbles will eventually get sucked up the U tube and collect there into one large bubble. Your flowrate MUST be great enough to force this bubble on out the other end of the tube, or you run the risk of losing your siphon prime.
For what it's worth ...
Brian

 

[krustytheclownfish]

Ah, the light has come on. Thank you.