shutoff valve

[RaphaelReef]

Ok guys I didnt think things through all the way when I setup my 150display I have a sump. is there a way to add a automatic shutoff valve to a preexisting setup? I dont want to have to take stuff apart

[thegrun]

Auto Shut off what?

[Fizz71]

Originally Posted by thegrun

Auto Shut off what?

+1 on confusion.

[RaphaelReef]

Sorry at work typing on my phone. I should have explained better. I need to add a shut off valve the sump tank so if the power goes out it doesnt overflow. Right now my return pump has to stay running

[thegrun]

If you were to add a backflow preventer you should add it to the discharge side of the pump, but reliance on a BFP is a sure receipt for a disaster. Any BFP will eventually fail due to calcium deposits, sand or detritus build up, so your sump design needs to be able to accommodate all the drain down water. Drilling a small hole near the top of your returns to allow air into the lines when power is off will help limit the amount of drain down water, but the bottom line is your sump has to be sized to accommodate all the water that flows down when the power is off or eventually you will have a flood and potential fire.

[cobraz]

I would not use a one way preventer. Case in point of calcium. It binds to the walls of your pipes and valves... in time it will fail. I had one fail on a 125 ...when you come with the wife and 50 gallons of water is on the floor. The look is priceless.

[RaphaelReef]

But if the power is off how will my pump work anyways. Thats why I was thinking a shutoff valve to keep the tank from draining

[johnwick]

Try to position your returns to be just below the water line so that when the pump shuts off a limited amount of water returns back into the sump. I agree with all others above that a check valve is not a good idea and will fail.

[thegrun]

There isn't a good way to prevent the tank from draining but you can minimize the drain down water volume by planing your installation to keep the returns high in the tank and by drilling a small hole near the top of the returns to prevent a siphon.

[Fizz71]

Is the problem because water is pulling back from the pump return (a siphon) or because more water is draining on the overflow than the sump can handle? ..or worse?

If it's the pump siphoning back you can add a hole to make a siphon break and use a check valve for backup. If it's too much water overflowing you either need to keep less water in the sump when it's running or re-design it.

Murphy will always fail your system at its weakest point...you need to avoid flooding by design, not by an automated process because that's what will fail 2 years from now when you least expect it.

So lets start with where the water is coming from on a power outage and how much water we're talking about and we'll go from there....

How big is your sump? A photo would be helpful too!

[RaphaelReef]

My concern was just when the power goes out and no pumps are running to return the water. Everyone talks about turning off there pumps for different things but if I turn mine off the water will drain into the sump with no pump running to return it and it will overflow

[gone fishin]

If your sump will overflow that is bad. A well designed sump will not overflow. You must answer some of the previous questions for some help.

How big is the sump?
How much water is in the sump?
How big is the display tank?
How deep are your returns in the DT?
Do you have syphon breaks in the return lines in the DT?

[scuzy]

Sounds like your sump is too small and cannot accommodate for the amount of water that drains back into sump when power is out. A siphon break would help but if your return pipe is not set right it's a problem waiting to happen.

[LJLKRL]

You need to adjust your drain pipe from the display tank to the sump so when the return pump is off, only the amount of water the sump can hold will drain into it.
The drain pipe opening needs to be high in the tank to limit the amount of water that can fall into the sump with no return pump.

Once that point is determined, you should mark your sump at the highest water level with a piece of tape or a grease pencil. Also mark the normal operating level so you know how much fresh water to add for topping off.

[Fizz71]

The bottom line here is a running tank has water "in suspension"..that's normal. That water should be the sum of the amount of water above the bottom point of the teeth (weirs) in the DT overflow and the amount of water in the pipes.

A properly sized sump will run about 2/3 full with water so when the power goes off the suspended water falls in the sump and fills it up, but doesn't overflow. The power turns back on and it goes back to normal.

You will also get some water from the return pipe that will create a suction when the power stops and pull water back into your sump until it sucks air so you have to either make sure the siphon breaks with a hole, or have the top of the pipe exposed so it sucks air right away and stops.

If your tank is draining more than a 1/2" or so you've got a design problem.

Here's Melev's page, although the animation is for an overflow box, not an internal one.
http://www.melevsreef.com/what_sump.html

[RaphaelReef]

thanks fizz that helps alot. I'm going to redesign my sump here soon and for now just hope nothing happens I have it on a battery back up so it shouldn't shutoff

[RaphaelReef]

Hey fizz check out my diy thread would like your opinion

[coralsnaked]

Do you have your drain in an overflow box or a stand pipe exposed directly to the display. Because if you have no back siphon problem from the return acceclerators then only other problem when pumps go out would be water draining down the standpipe. An overflow box minimizes this problem.

[Fizz71]

This thread is basically going to be continued here:
http://reefcentral.com/forums/showthread.php?t=2308939
..so nobody else has to look it up.