Accounting for sump power outage?

[Moloch]

How do I know how much space to leave in my sump in case of a power outage? If I understand things right, the water level will be right even with the top of my overflow, which means in a power outage the DT won't drain at all, just the water in the overflow (excluding what will remain due to the siphon break). Is that right? So I just need to figure out how much water will be in my plumbing at any given time?

How do you keep a siphon from occurring on the return side? If the return in the DT is submerged, won't it siphon back down through the pump and drain the tank until its below that return? Or is that normal and something you account for?

I'm trying to figure out how much room I need to leave in my sump for this without too much trial and error...

 

[twilight zone]

You can drill a hole in the return pipe like a 1/2 inch under the water level. When it siphons back and reaches the hole the air will break the siphon. For the size of the sump, bigger is always better as long as it fits in the cabinet. You have to look at the pump size too. If your flow is too fast, it will overflow your sump if the power goes out. So you have to dial down the pump or get a smaller pump. After every is dialed in, you have to do a shut down test to see if it overflows when it is unplugged. Good Luck.

 

[stingraybob]

Im getting ready to do the same thing, and boy oh boy am I dreading the flood

 

[cichlid2006]

To get the right amount of water in the sump and tank:
1) Fill the tank to the tipping point, i.e. where water is just about going over the edge of your overflow or back flow down the return lines but never does.
2) Fill your sump to whatever maximum water level you want taking into account the volumes needed in the pipes to fill the tank and the water needed to tip the water over the overflow. I still leave a couple of inches at the top of my current sump to account for decor changes which will push water levels up/down.
3) Turn on the pump and watch as your sump does its thing.

No mods, no drilling, no extra pipes, no extra valves, no extra anything.
This way you can relax knowing that you filled both to maximum when the power was off so nothing can possibly overflow. This was the list my tank builder gave me as I had never used a sump before and was a bit out of my depth. Never caused me any grief and there is always plenty of water in my sump when running at full steam so my pump never runs dry or even close. HTH

 

[malawi500]

thanks for the post above, but still not clear. Would this work:

1. Put in all rocks/substrate into tank and media into sump
2. Close valve on drain pipe
3. Fill up so drain pipe is fully submerged and water just starts to trickle down emergency drain. Stop water
4. Open valve on drain pipe, water will flow into sump. Level in tank will drop to drain pipe level
5. Then fill up sump with however much water you can fit in sump but leave a few inches from top
6. Switch on pump and allow to do it's thing
7. Adjust drain valve to allow correct water level
8. Mark new sump level

I am about to do my first sump, so want to check this will work

 

[Egon]

I fill my sump up and run the pump and get everything stabile then turn power off and wait. If my sump is going to overflow I turn power back on to prevent a spill. Then I drain a little water from the sump and turn power off again. Hopefully you get to a point where your pumps have enough water to run and your sump wont overflow when the power is out. When I reach that point I mark it with a sharpie that says "water level with pump on". After water changes and other maintenance I make sure to fill the sump up to this level and no more.

 

[cichlid2006]

1. Put in all rocks/substrate into tank and media into sump
2. Fill up so the main drain pipe is fully submerged just before it starts to trickle down the main drain. STOP FILLING. No water should be going to the sump yet.
3. Fill the sump to the desired level taking into account that the return lines need to be filled and extra water is needed to push the water in the tank over the overflow.
4. Switch on pump and allow to do it's thing.
5. Once everything is filled to the correct level mark your sump with a maximum fill line.

If the you notice the pump starts to run dry or you suspect it might run dry then switch everything off and add more water to the sump. Do this until you get the right amount to run get water over the overflow, fill the return line(s) and not run the pump dry.

You won't flood in the event of a power cut.