overflow and return pump question

[petere1989]

So I now know, thanks to a lot of you on here, about water level in sumps and that you want it so if the power goes out to be able to fill the sump without overflowing. But here is the question I have. What happens when the power comes back on? The syphon stops, and the return pump will turn back on, emptying the sump and overflowing the main display tank. Is there a way like, with a power bar, or something, to have a fail safe, so if it looses power to not turn back on? I have it ok so if the power goes out it won't be a problem but when the power turns back on, I don't see how it won't overflow the tank and empty the sump.

[Shaummy]

Depends on what kind of overflow you have...if you have a siphon type of overflow or overflow box, it should have a way to maintain the siphon so that when the power comes back on, and the water level rises, the flow will begin again.

I think there are types of external overflows that have small pumps attached to them to start up the siphon again.

If you just have a gravity drain, when the water gets high enough, it just drains to the sump again.

[GroktheCube]

Originally Posted by petere1989

So I now know, thanks to a lot of you on here, about water level in sumps and that you want it so if the power goes out to be able to fill the sump without overflowing. But here is the question I have. What happens when the power comes back on? The syphon stops, and the return pump will turn back on, emptying the sump and overflowing the main display tank. Is there a way like, with a power bar, or something, to have a fail safe, so if it looses power to not turn back on? I have it ok so if the power goes out it won't be a problem but when the power turns back on, I don't see how it won't overflow the tank and empty the sump.

Why wouldn't the drain restart? Are you talking about a siphon overflow box vs drilling? That is one reason that people recommend drilling vs siphon.

If you have a tank controller, you can tell it to keep the return off in the event power fails and is restored.

[Vinny Kreyling]

Like Shaummy said, the siphon never breaks in properly designed external overflow box so it starts up no problem.
With internal overflows when the water rises enough to fill the drain tube it also starts by itself.

[Dozer1one]

When you loose power to your home you should always shut off your main breaker to avoid surges to you appliances when it kicks back on. Then at that point you control start up anyway

[petere1989]

Originally Posted by GroktheCube

Why wouldn't the drain restart? Are you talking about a siphon overflow box vs drilling? That is one reason that people recommend drilling vs siphon.

If you have a tank controller, you can tell it to keep the return off in the event power fails and is restored.

I'm talking about a siphon overflow. I wanted to drill but I didn't get the sump until the tank was already set up. but yea, I also have an aquacontroller from BRS.

So the siphon shouldn't be broken? I don't see how it wouldn't break but maybe i'm wrong.

[Shaummy]

what kind of overflow do you have or snap a pic??

[Vinny Kreyling]

The exterior overflow box should have 2 compartments.
1- water drains to sump
2 -water is held here even after the rest drains
2 -is where the siphon tube remains all the time
the siphon NEVER breaks unless an air bubble accumulates inside the siphon tube
IF this happens increase the flow so the water running pulls any air bubbles with it out the tube.

[EllieSuz]

I have a LifeReef external overflow box and it never fails to re-start after the return pump has powered down. Not all overflows are created equal and the kind that need a pump to sustain a siphon are prone to flooding. There are two "safe" overflows that I know of and both have a U tube where each end of the tube is in water whether it's running or not.

[petere1989]

It is a Eshopps PF-800 Overflow Box 600-800 GPH. if you want a picture of the box, let me know.

I see what you mean though, the u-tube is long enough that it should hold water regardless. I think the thing to do is to power everything off to make sure that it works correctly.

[examiner]

Like Eileen said, if both ends of your siphon tube remain submerged when the pump is off, it *should* restart automatically. Your overflow box probably has a divider in it to break it into two sections. The u-tube should go into the section that doesn't contain the drain. The divider will retain water even when the flow stops, and that's why both ends of the tube will still be submerged.

Dealing with air bubbles can be a PITA though.

[Shaummy]

Yep..exactly as Vinny and Ellie have responded. I looked at that overflow box and it indeed has two compartments, one that the U-tube would stay submerged in and one that drains down to the sump.

I had one similar to this before I drilled my tank and it always started back up. I did keep an eye on any large amount of air accumulating at the top of the tube, but never had a problem overall.

[fishgate]

The bigger thing is that your tank should hold any sump volume that would be pumped up in the event of a siphon failure and your sump should hold any tank volume that would drain down in the event of a pump failure. I have a 125g with a 40g sump and there is no way to have a flood on either end regardless of what component fails. This is the surest bet.

[petere1989]

cool. thanks for all the help!

[EllieSuz]

I routinely check that little hole we drilled to be sure it isn't clogged with something like one of those tiny snails. When I do a water change, I stick a little brush in there to keep it open. Other than that, I never think twice about my overflow starting up. It made me nervous at first, but now, I take it for granted. You should not get an air bubble in the tube. I'm pretty sure that means your return pump isn't producing enough flow. What kind of pump are you using? When you started it up the first time, did you put an airline hose in the middle of the tube and draw the air out of it?

[MrClam]

If you matched the output of your return pump to the overflow then the flow of water through the U-tube should prevent bubbles from accumulating. Some people have issues with that because they want to be "safe" and get an oversized overflow box but this actually creates more risk. A properly designed external overflow is as safe as a drilled tank.

[Ant1matt3r]

I have a CPR overflow box that has a nifty feature - It has a small nipple that you attach airline tubing and a dosing pump to - it ensures that there is ALWAYS a siphon when power returns. That, and I also got an IBM battery backup to ensure the system runs, despite a power outage.

[petere1989]

Originally Posted by EllieSuz

I routinely check that little hole we drilled to be sure it isn't clogged with something like one of those tiny snails. When I do a water change, I stick a little brush in there to keep it open. Other than that, I never think twice about my overflow starting up. It made me nervous at first, but now, I take it for granted. You should not get an air bubble in the tube. I'm pretty sure that means your return pump isn't producing enough flow. What kind of pump are you using? When you started it up the first time, did you put an airline hose in the middle of the tube and draw the air out of it?

The only bubbles i'm getting now are from my skimmer (which is like microbubbles from hell) but other than that, plugging the hole that I drilled stoped all of the large bubbles. It was drilled outside of the water. I drilled one in the water and now theres none of the extra large bubbles, like i said, only ones from my skimmer. I didn't even know I needed to extract air out. I just turned it on, and set it down in my tank and there it sits. Should I do anything to it now? it's been running for about 24 hours now.

oh and my overflow says that it does 600-800 gph, and the return pump is doing 500. I think its just an ordinary pond pump. It was the only one that my LFS had. He had a used one that did about 1000 gph, and he tested it and it didnt even work.

[petere1989]

Originally Posted by Ant1matt3r

I have a CPR overflow box that has a nifty feature - It has a small nipple that you attach airline tubing and a dosing pump to - it ensures that there is ALWAYS a siphon when power returns. That, and I also got an IBM battery backup to ensure the system runs, despite a power outage.

could you tell me a little bit about the IBM battery backup?

[Spaughdevin]

just take a few minutes one afternoon and run a test. Cut off the power to your tank until it drains all the way down and then turn the power back on. Then pay attention and see what happens. Its as simple as that. Good luck