Overflow without durso?

[neomarz]

100G Custom Trap shaped acrylic tank with two 1" drains and builtin overflow. My question is can I run the overflow without durso pipes and just let the natural overflow from the return to drain both 1" drains on gravity to sump?

I am running a 650gph return pump with about 36"-48" head. I do have wr8 webao creating more flow within the DT.

Any pros and cons to runnning this at such a low return rate?

Tank acrylic thickness 1/4" / Front 3/4"

30G sump FYI

 

[falconut]

Typically durst pipes are to reduce or eliminate the noise of the drain. Durso's wouldn't fit in my overflow, so I used a stockman.

If I understand your question correctly, you just want to let the water flow down the hole or into the top of a stand pipe. If this is correct, it will probably be noisy and gurgle.

 

[neomarz]

I want to just let the water drain into the overflow box, down to the two 1" bulkheads in the bottom of the overflow box. No pipes in the overflow box. I believe I should get around 300gph thru each drain gravity and the return pump is 650gph with about 36-48" head.

Do you think at such a low flow rate this will be noisy? Any cons to running this way?

Drains are both 1" bulkheads with a straight 32" drop down into sump

 

[Flippers4pups]

There will be a "waterfall" sound from the water falling to the bottom of the overflow. Next there will be very noticeable "toilet flushing" sound from water and air going down the bulkheads and pipe.

You will hate it!

 

[gallegos]

Will be loud as said above but you can do it

 

[neomarz]

Any suggestions on a more silent method? Based on the dimensions of the tank what would be the ideal height for each tube for the method?

 

[thegrun]

I would put the emergency drain's top at the same level as the bottom of the slots between the teeth of the overflow box. The primary drain should be two 90s if you have room in the overflow box with a 3/16" hole drilled at the top to allow air out. If you don't have room for a double 90 you could simply use a straight pipe but it's top would need to be at least 2" below the emergency drain. For both situations the primary drain needs a gate valve near the bottom of the drain line so you can adjust the flow.

 

[neomarz]

I appreciate the help guys. Do you think there would be need for much adjustment with the 1" drain flow rate with a 650pgh return pump?

 

[thegrun]

Yes for sure. The best way to silence the drain is to use a gate valve to back up the flow so the water level inside the overflow box is just below or at the same elevation as the top of the emergency drain

 

[Flippers4pups]

Yes for sure. The best way to silence the drain is to use a gate valve to back up the flow so the water level inside the overflow box is just below or at the same elevation as the top of the emergency drain

This^. The other way is to leave the main drains wide open and adjust your flow from your return pump. This is done (given your return pump has more flow than you need) by putting a tee off the return line with a ball valve to feed a manifold. The manifold is used to feed reactors, UV's ....etc. The excess flow is then returned back into the sump. By adjusting the ball valve you can adjust the flow into the DT and thus adjust the water height in the overflow.

 

[neomarz]

I am running 2 1" drains. One emergency drain and one regular drain. I am having a problem with getting a full siphon on the main drain. I am running 3/4' tubing on the main drain and 1" on the emergency. I did the 2 90's with the elbow facing down but the water seems to only fluctuate up and down. I did drill a small hole in the top of the elbow but still cant get a full siphon.

 

[Potatohead]

If you have two drains in there I would run a Herbie setup. Much quieter, all you really have to do is extend the one drain with the gate valve about 1" from the top of the overflow and then extend the other emergency drain even with the top of the overflow (or maybe 1/8") below.

Also it sounds like you would have about 6x flow through your sump which is totally fine.

Edit - just noticed your post above, do you have a gate valve on your 3/4" drain? There's no way you'll get full siphon if not a 3/4" drain at full siphon will flow way more than your return pump.

 

[neomarz]

Drain does not have a gate valve. But my return pump is rated at 650gph. My return pump seems to be pumping out more flow than I am receiving. I did have my 3/4 drain at full siphon before with the same pump and it worked great. But with the herbie i cant get a full siphon.

 

[Potatohead]

It's not a Herbie without a gate valve on it. A 3/4" drain at full siphon flows something like 800 gph, your return pump is not going to achieve that it seems so you need a valve or a bigger pump. Problem with a bigger pump is you'll be turning your tank over more than the recommended 3-6x per hour and it's going to be virtually impossible to get the drain and pump matched equally, a gate valve lets you adjust tiny amounts at a time

 

[neomarz]

Ok so i double checked the return pump. And its stated for 620gph at 11.5 ft of head. I am only running about 4 feet of head so I believe i am getting more than 620gph return. On my previous tank I had a 3/4 drain at full siphon with a 2nd 1" drain on gravity and it worked perfect. Just enough flow for the return.

But now with the stand pipes I cant get the full siphon.

 

[Potatohead]

What pump is it? 600 gph at 11' is a pretty serious pump, at four feet it should be WAY higher, like maybe as high as 1200 or so, certainly enough to reach full siphon. Is it possible the pump is adjustable and you have it turned down?

 

[neomarz]

The pump is a Pacific hydrostar fountain pump item # 68393. I got it at harbor freight. Max head lift is 11.5 FT. I figured this may be the case because Im under half head lift, so the flow is much more. Even at full 3/4 siphon I still needed the 1" 2nd drain running on gravity to match the flow.

 

[Potatohead]

Ok, this makes sense. The pump will be rated at 620 gph with no head. This is how they're all rated. So at 4' it's probably like 350 or something which is why you're not making your siphon. It will work fine if you add the valve to the drain.

 

[neomarz]

How can it only be at 350 if it can handle the 3/4 drain at full siphon plus the 1" drain on gravity? The pump would almost empty the sump if I did not add the 2nd 1" drain on gravity. It evens the flow out so the return and drain work seemless

 

[Potatohead]

I'm not sure what do say about your previous tank, but something is not adding up. The pump doesn't care if it's filling the overflow or not, or where the water drains, the only difference is you're adding another gallon or two of water to the system to fill the overflow up. All pumps are typically rated at zero head and with no inlet restrictions. A pump with 620 gph at 11' of head would be rated at around 1500 gph. The only thing I can figure is maybe your previous drain had lots of elbow or restrictions in it? That could severely limit flow.