How big of a Sump "pit" should you have?

[takagari]

After looking a lot, I've come to a question that concerns me.
I'm designing a drip system, with an overflow in the sump.
But when I look at all the plumbing etc. It seems to me that one would need a large sump reservoir.

If I lost power, and all my piping drained etc. this would all go down the overflow into the drain.
When power kicked back in, if the sump wasn't holding enough water, could the pump not quickly run itself dry?
Am I overthinking how much volume is in the pipes and will over flow?

So I'm planning a fairly large area behind my baffles to cover for this.
Thanks for any advice

 

[celebrist]

You need to test it out and see what your water level in the sump should be to be able to handle the influx from a power outage as well as avoid running your pump dry.
Some people run large check valves to reduce back flow during power outages

 

[ragin_cajun]

You're not overthinking at all. You're thinking exactly right. Your sump needs to be big enough to hold all the water that's gonna fall out of the pipes when the power goes out.

The return lines from the pump that go into the pump, that end in a nozzle or a spray bar or something.....you probably have that line under the water level in the display tank....that can catch siphon and start draining if the power goes out. That's why Mike mentioned people using check valves.

I have 2 check valves in each of my return lines.

 

[rodger]

I use the kind of check valves that use a weighted flapper. The spring loaded kind failed after a few months.

 

[fishguy306]

I think you guys might be misunderstanding what T takagari means.

When you have a constant drip setup, the drain in the sump for the drip is always the high water line. So when power goes off XXX gallons flow into the sump from the tank and the lines. Could be a couple if the tank is small, could be 50+ like on the system I'm building.

If I understand correctly the question is how to size your sump to account for the excess water flowing out of your sump and when the power kicks on the lower water level?

If so I don't have a good answer. I wasn't able to get one when I asked the question besides make the sumps large enough that they wont run dry when the water comes back so they are given time to refill by the drip. Not sure how easy that'll be in your case, mine it wasn't too much of an issue as I've got a dedicated filter room.

 

[rodger]

I think you guys might be misunderstanding what T takagari means.

When you have a constant drip setup, the drain in the sump for the drip is always the high water line. So when power goes off XXX gallons flow into the sump from the tank and the lines. Could be a couple if the tank is small, could be 50+ like on the system I'm building.

If I understand correctly the question is how to size your sump to account for the excess water flowing out of your sump and when the power kicks on the lower water level?

If so I don't have a good answer. I wasn't able to get one when I asked the question besides make the sumps large enough that they wont run dry when the water comes back so they are given time to refill by the drip. Not sure how easy that'll be in your case, mine it wasn't too much of an issue as I've got a dedicated filter room.

There is almost none with check valves. I've been shopping for them for next years pond project. Pentair has 2" ones.

 

[millerkid519]

There are a few questions I have to ask to answer your question or atleast send you in the right direction. What type of overflow are you using and size of drains? Gph threw the sump? Level you plan on running in the sump? Size of pump chamber?

 

[ragin_cajun]

Matt --

That's exactly what happens in my sump. I have a drip system, water level in the sump is the top of a standpipe in the sump that goes to a drain out of the house. When electricity goes out, plumbing drains to the sump, level is higher than the sump standpipe, so it all drains out of the sump.

Electricity comes back on, pumps fill up the plumbing again, and the water level in the sump is low until the drip system catches up again.

The solution is to have a big enough sump to account for all this, or you could possibly add some baffles in the sump to alleviate all this.

A "big enough" sump on a 540 gallon tank with 2 inch drains and 1.5 inch returns is 125 gallons.