Plumbing two sumps

[ecam]

I had a plumbing question. I linked to Tanks together a 120 and a 57 gallon. The current sump cannot handle the total water siphon. So I need to add an aux sump which will only be used for emergencies when the return goes off.
The problem I can't figure out is how to make sure all the water in the aux sump goes back to the main sump when the power is returned. The sumps sit 2 ft about. Any suggestions?[/QUOTE]

 

[Loki]

Yeah. Depending on how much room you have you could do something like what I did.

[tapatalk isn't letting me upload the photo. I'll try again later.]

I have two 40b as sumps. The first I put 2 two inch holes in to drain into the lower sump. If I ever need to I can adjust the level in the first sump by 3-4 inches easily and give me more room for water of something was to happen.

The lower sump only contains my skimmer and the return pump. The skimmer section is 10" of the tank and the bubble trap takes up another 3". So that leaves 23x18x9 for my return section. I have turned the power off and added 10 more gallons to the lower sump just to see how much it would hold if my 10 gallon ATO got stuck on and power failed at the same time (impossible but I did it anyway) and it held all of it.


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[ecam]

But in a power outage wouldn't water continue to go from the upper sump to he lower sump and cause it to overflow?

 

[Loki]

No. Since the lower sump runs at 9" it has another 9" or 20 gallons it can handle before overflowing.


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[kschweer]

Hey Edwin I sent you an email. Think I figured something out.

 

[Chompers]

If you do two sumps, they must be on the same level. Other wise, you still only have one sump to handle the drain down volume. They also must have an equalizer line connecting them. You can't do two sumps with separate pumps without the equilizer line because one will over take the other (one will overflow and the other will suck dry).

At this point in time, you are better to just do two separate systems. Or get one sufficiently sized sump.

You will have to put your thinking cap on and do some math. You need to know the volume of water that will drain down from the display tank (and from a raised refugium if applicable (as in Loki's system)). The formula is LxWxD. Keep your calculations in cubic inches and don't worry about converting to gallons (you will have to convert back to cubic inches anyway). With knowing the drain down volume, you can then calculate the sump volume needed to handle it. Keep in mind that if you have twenty gallons of drain down water, that a twenty gallon sump isn't going to cut it. You will need a sump with more than twenty gallons of unused space when the sump is at it's highest operating level.