Would this design work? I've never built one before.

Pull a siphon (via mouth) on the 'in' tube
water flows down and on to filter floss which is on top of the drip tray
water flows over bio balls/pot scrubbers
water flows in bottom section, sump pump pushes the water back into the tank via 'out' hose.

I think this should work. The 'in' tube and overflow box would only be about two inches down into the tank. This would prevent dumping the tank in the event of a power outage.

The sketch doesn't show it, but I am planning on adding a flow control valve to both the 'in' and 'out' lines to make it easier to balance the flow rates.

Thoughts?

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Yes this design would work. But there is one, IMO major drawback to this type of system. If you lose power and your "in" line loses, it's siphon wont restart on its own when power is restored. And this can lead to your return pump emptying your entire sump into your already full display tank. This is the problem I am working with right now. I have found one design that will start itself but it requires drilling the tank. Here is a link to that design. BeanAnimal's Bar and Grill - Silent and Fail-Safe Overflow System

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It has become more than a hobby! My 29gal Dream Reef DIY Build

I am in the process of building a sump myself ATM. There are several ways you can accomplish building a continuous siphon overflow. This is one I built last week.
Aquarium Gallery - Completed DIY Overflow

I did scrap that one and build one that is twice as tall (~16"). The one that is pictured is about 8" tall and didn't have enough flow. the taller they are the faster they flow. A PVC overflow will run you around $15 - $20 for one like I made. They are a relatively easy to assemble and work really well. If you search youtube for "DIY overflow box" or "DIY PVC overflow" there are a ton of videos to watch. If you have any questions feel free to PM me.

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75 Gallon Planted

Thanks TYTH. What pump are you using for the return? I'm trying to pin down how many gallons per hour I need.

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I don't have my system set up just yet but I am getting a CA 1800 and have two 1" PVC overflows for the inlets. The CA 1800 is supposed to get 635 GPH so after accounting for head loss I figured I will be getting around 375 - 400 GPH.
As far as your turn around goes I figure roughly 3-5 times your total water capacity should be your flow rate. The reason I say 3-5 times for a sump is because a HOB filter it's supposed to be at least 4 times turn around is good but with a sump you have a ton more media for BB to grow on which means it is doing that much more for your tank. Also your water capacity is increased. All in all you can really set your turn around to what ever you really want as long as the water flow is not to much for your fish.
I Almost forgot to mention that you want your overflow to be able to handle the same flow rate that your return pump is rated at plus a little extra to be safe in case you get a back up in the overflow. I also have a ball valve on both the overflow and the pump so I can adjust to have a constant flow.

Edit: I did test one side of my overflow this morning and it almost handled the equivalent to what the faucet from my washer/dryer hook ups put out when they are at full flow which is a considerable amount.

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75 Gallon Planted

Good. That's about what I had planned for. I'm looking at the sunterra 137016 pump that has 8' max lift and 320 max gph. I've got an old 15g hex that I'm using as the sump tank. I've got the dividers cut (the white plastic sheets with the square holes in it), plexiglass drip plate (what'd you use?) also have 500 1" bio balls on the way. Need some pvc and tubing now

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You might look up pvc overflows (beaslbob trap ?). Much less expensive then overflow boxes.

No valves on drain or return are required. the drain will balance out the return with no adjustments.

Be sure you have some mechanism/design that will prevent floods when the media fills up.


be sure to

1) test power out. (floods of the sump including the siphon on the return lines)
2) power return (normal oeration returns).
3) drain failure (siphon break, blackage) to insure the upper cantain does not flood before sump runs dry.


my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Are you talking about a pump that pumps water from the display tank to the sump? If so that is a REALLY BAD IDEA. If he decides to build a DIY overflow a properly designed and built overflow can handle 2000+ GPH depending on how big the overflow pipe is. there is no need for a pump from the display to the sump. Let gravity do it's job.

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75 Gallon Planted

There are overflows on the market designed to startup siphon once power is restored. If it didn't by chance and the entire sump did empty into the display tank, there still wouldn't be an overflow issue as eventually there would be no water to pump out. The display tank would never be full if water had been draining out like it was supposed to before power died. In fact after a power loss, the water will continue to drain into the sump until siphon is broken and that is usually at the point of a near full sump - near full sump = tank 2-3 inches low. I have tested mine many times for power loss and overflow box siphon loss and never came close to overflow in either tank or sump. The fail safes have to be in place and functioning and if they are, it theoreitically could never happen.

Sorry for any confusion.

the only pump is from the sump to the highest container.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

I was hoping that is what you meant. I guess I was a little confused when I read it.

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75 Gallon Planted

actually even that isn't quite correct.

the only pumps are from the sump to higher containers.

I guess it would work if you had more then one pump
But all the pumps must be returning water to a high container.

(But then why would one do that anyway?) Just to keep is simple the sump pump returns water to the highest container.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Thanks everyone. Currently waiting for the rest of the bioballs to come in. The person I ordered from on Ebay only sent me half of my 500 ball order. So, a bit stalled at the moment. Will update with pics as things progress.

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