Problems with overflow too slow

riuqlav

Feeder Fish
MFK Member
Dec 3, 2019
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I'm trying to do this overflow system:
IMG_20200124_214808.jpg

So I found some flexible pipe for a good price and a diagonal T PVC pipe.
IMG_20200124_200829.jpg
(Ignore the grey tube, is my current filtration)

I filled the tube till the top, and suck the air out of the first curve, making the siphon until the T joint.
I positioned the T where the water level is, to drain to the sump.

It starts and stops exactly where I want, but is waaay too slow, the pipe is just pouring water slow and steady. It accelerates if I get the T joint lower, but when I simulate power outage it floods the sump.
The only thing I did different from what I see online is the flexible pipe and the diagonal T, I supposed it wouldn't be a problem since is primed until the T.

I know nothing about plumbing, so any help to make it work will be appreciated!
 

TheWolfman

Goliath Tigerfish
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Sep 5, 2010
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first off welcome to the forums. Diy overflows can be a ticking time bomb waiting to go off and most hobbyist will recommend to drill the aquarium and install a bulkhead instead. Ulu Ulu is our resident diy overflow guy hopefully he will chime in. Your in uncharted waters with the flexible hose, as I haven’t seen anyone yet to try it with a diy overflow. I would recommend you do some research on sump plumbing to better understand what your trying to do. I would also recommend you ditch the hose all together and make it out of pvc, as well as increase the diameter of the size of the plumbing. General rule of thumb is twice the size of the return for you drain. If your using 1/2” pvc for your return pump then you should be using 1” for your drain. It does get a bit more involved then that though. What size return pump are you using?
 

riuqlav

Feeder Fish
MFK Member
Dec 3, 2019
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Thanks for answering, drilling the aquarium 1.5 cm thick glass is out of my skills even more then plumbing.
I'm using 1 inch pipe to pump water up and 2 inches to drain.

Actually the overflow starts and stops correctly, the problem is being waaaay too slow for my pump almost dripping, my pump is 4 Metres height, 5000L/K even regulated on minimum.

I just need to make the tank drain quicker, my guess is air bubbles inside the tube restricting the flow, but when I put the T joint lower it jets water like a firemen's hose so I don't know where I'm failing.
 

riuqlav

Feeder Fish
MFK Member
Dec 3, 2019
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It's strong, but there something wrong, currently I have a 2 inches on siphon dealing easy with the pressure of the pump.
In the other hand this is the overflow on the right level. Empty, just trickling.

IMG_20200124_200845.jpg
 

twentyleagues

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Apr 5, 2017
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Those DIY overflows are such a PIA.
So to understand your issue better, is your pump running out of water the way it is currently working?
You said you flood the sump if the power goes out if you lower the t, but while power is on is the pump able to keep up?
Which t are you refering to?
My understanding is you will need to drop the y down more. Is this the "t" you are refering to?
How deep does the pipe go in tank? This will dictate how much water will return to your sump during a power outage. Basically raise the intake. In the diagram there should be a u inside the tank with a pipe heading back to the surface to regulate how much of the tank goes to the sump. Seems that may be missing?
 
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twentyleagues

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Currently the diagram shown will allow the tank to drain to the level of the pipe in the tank. So about half the tank will go to the sump during power outage.
 

riuqlav

Feeder Fish
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Dec 3, 2019
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Yes you're right, I can make it keep up with the pump, but I need to put the Y joint* lower than it should be, so when I take down the power it floods.

I can fold the point inside the tank upwards there's plenty space but I don't think it will make much of a difference in velocity...

This is the video that I took that from, apologize is in Portuguese, but you just need to follow the animation is quite short.

 

twentyleagues

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Well in my thinking lowering the y will allow a higher flow rate. Putting the intake up higher in the tank will allow less of the tank to drain in power outage. Using flexable line is outside any of the videos or diagrams on this subject as all the ones ive seen use ridged pipe. I dont know how that effects flow dynamics.
All that said ive never had one of these systems work long term properly yet. All of them failed in one way or another way to often for my liking. Typically failed to start a syphon after power was restored causing an overflow of the tank or a dry running pump which burned up the pump. To risky for me.
 

riuqlav

Feeder Fish
MFK Member
Dec 3, 2019
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Well in my thinking lowering the y will allow a higher flow rate. Putting the intake up higher in the tank will allow less of the tank to drain in power outage.
This I didn't try yet, it might work if I find the right spot.

Using flexable line is outside any of the videos or diagrams on this subject as all the ones ive seen use ridged pipe. I dont know how that effects flow dynamics.
Me neither, I'm starting to think there might be a reason, because at least for me they were cheaper and faster that put together than a bunch of pipes and joints, but still doesn't make sense to me...if it's everything in the same basic shape and filled with water why wouldn't?
 
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