Flow rate through a siphon?
 

I built my own HOB overflow, which would work great if it could keep up with my pump.

I made it a BeanAnimal, so the box has a siphon and a durso standpipe and an emergency standpipe.

But the problem is, when the siphon that goes to the sump flows less then the pump is returning, forcing the waterline in the box to raise to the durso, the flow lessens through the siphon between my tank and the box.
I think this is because the waterline is higher, so there is less difference between that in the box and in the tank.

I want to, at least figure out the flow capability of the siphon between the tank and the box, which is 1 inch diameter, a 1 inch difference in waterline, and the siphon goes 6 inches sideways.

in the link below, a) is 1 inch, and b is 6 inches

http://www.calctool.org/CALC/eng/civil/hazen-williams_g

Thanks!

I get a calculation of almost 15g per minute or roughly 900gph thru your siphon

Yeah but that is talking about a siphon that is a straight tube, where mine is the kind where you suck the air out and it flows up, over the edge, and back down.

From what I can gather, that kind of siphon has different dynamics and lesser flow. Definitely not 900gph, cuz my pump goes to 900gph and I have to turn the dial all the way to lowest setting (probably 250gph) and still, the overflow can't keep up.

I really really want to figure out what I can do, because I already invested so much time and money into this system and can't afford any more of either!

Thank you :)

1 inch "U" tube you are looking at ~600gph safely..
But I don't think that what you have...

Please post pictures or a diagram so we can see what you actually have..
I'm really not understanding your whole setup.. Please don't tell me its that silly king of diy trombone crap..

Sorry for the crude drawing.
1 is the siphon one inch diameter between tank and overflow box
2 is the weir inside the tank
3 is the clear box outside the tank
4 is the siphon to the sump
5 is the first overflow pipe
Water level should be at durso pipe, so that a little flows down. But when the water level is this high, about 1 inch below tank surface, it can't keep up with my pump on the lowest setting. This has to be the number 1 siphon that reduces flow, right? Everything else is more than capable of supporting over 1000gph.

Really, this is like a recreation of something like an eshopps hob box, but set up to be like a bean animal. And costs half the price.

Bean uses 3 pipes to the sump.
More like a Herbie but that uses 2 Open pipes.
NO durso configuration.

Looks like a disaster waiting to happen.

Whats your plan to restart the siphon on the u tube when the power goes out?

Why not just drill a couple holes in the tank? much simpler and safer.

If power goes out siphon can't stop. It's basically a DIY HOB overflow, like Eshopps or Lifereef or CPR, but I can't figure out why it can't get the flow I need.


I honestly would love to drill my tank, but to do so would require such an insane amount of time, work, and money that maybe I could have a service do it, but definitely not myself.

Maybe I need to find someone who knows a little something about the physics of siphons ;)

How are you regulating water level in the tank to find this out?
Are you saying that you can get it to work just fine by lowering the water level in the display tank or is this water level you are talking about in the overflow box (3)?

Only until it gets enough air in the U tube which can happen over time. I"ve been in the hobby long enough to know that they do fail and will. The ones that utilize a aqua lifter pump on the u tube to evacuate air help prevent this but are still not full proof.

How much "amount of time, work, and money" do you have to clean up your house when you end up with saltwater everywhere?

If your in the hobby long enough I can just about guarantee that you will either drill the tank or replace it with a reef ready one.

Number 3 is in the overflow box outside the tank. The waterline inside the tank is constant with the weir.

Jamie, yeah if enough air gets into the tube at once I guess it could fail.
However, when I first primed it there was a significant air bubble. Because of the force of the water through the pipe, that air bubble is now gone. I can actually watch air go up the pipe in one side and out in the other side.

Of course it's not foolproof. It could absolutely fail. In that case, about a gallon or two drains from my sump into display, which I have allowed room for.

Is there a way to drill from the inside, with love fish and corals? If there is I'm all in.

Buy a CPR overflow box. Mine has only flooded twice - good thing it is in the garage

Ha! Only twice!
Yes I would rather drill my tank than let it flood my bedroom.

But here are the only says this could happen with my setup, that I know of.

1. The bulkheads on my overflow box leak. (They are lifeguard aquatic and where the threaded connectors meet there is some salt creep so gonna order different brand)
2. The overflow box legit breaks apart
3. The baffle between my return pump and rest of sump breaks.
4. Other various tubing in my sump for things like media reactors, etc. Leak.
5. The weir breaks and a third of my tank drains to the sump
6. My ATO box explodes. This is what happened last night! It was clean water though and I had lots of towels laying around so not horrible.

My issue that I'm trying to solve is that this box can't keep up with my pump when working properly. I want to either find an easy fix for that. Or figure how to drill my tank easy, from the inside with Liv efish.

Thanks KS!


Sent from my iPhone using Tapatalk

Or a power outage?

Well, if the power goes out, as long as nothing stated above occurs, nothing bad happens.
I have accounted for the amount of water that would be transferred between tank and sump if either overflow fails or power goes out.

The flow rate of the siphon has to be more than the return, you may need a smaller pump or larger pipes. Over time you will get air build up in your siphon which it why we run a nipple at the top of the siphon tube and suck water/air out of the top. Also over time your flow out the siphon will probably decrease with the build up of algae and crud.
You could drain water out of your tank and drill from the inside by taping something on the glass to catch the crud.
Cheers! Mark

What about when the power comes back on? will the siphon start back up?

Yes, the siphon never stops, because the drain in the overflow is above where the siphon goes. Therefore, the waterline never goes below the end of the siphon.

75 gallon tank is not a very big tank to drain, move a foot or two, drill and set back up.

From your other posts it didn't look like you had much in the tank. Get a few totes and/or buckets to put everything in. Buy a overflow kit with everything including the glass bit. Drilling a glass tank is really easy. Go slow and let the bit grind through the glass you don't technically drill through glass.

You'll be happy you did!

honestly, this is just like a eshopps overflow, just I made it my self....
https://www.google.com/url?sa=i&sour...26569987452473

The difference with mine, instead of baffles, the drains are just raised above the output of the siphon into the box from the tank.

But the more i think about what I can do to change this, the more I think it is just better to drill the tank. I mean, it would take a good full day or more and maybe another one or two hundred dollars or so, but I just don't want to keep finagling with overflow boxes anymore unless theres a simple fix im missing.

I'm gonna have the time in a couple of weeks, so as long as it's easy and I don't have to remove the tank from where I have it beside to get behind, then im all in.

Thanks

Your u tube will never flow as much as the drain line due to gravity unless you restrict the drain line. You could add a second u tube. It sound to me that just dialing back you return pump to match the flow of the u tube. I don’t think the overflow is as bad as everyone is making it out to be.
While I agree a drilled tank is a much better way to go, I also understand your reluctance to drill your tank. If you drill it you have to plan for the worst case. What will yo do with everything if the glass cracks or shatters?

I know you obviously want as much flow through your return pump as possible, but it seems like an easy quick solution to your problem is to put a ball valve inline on your return. Create some head pressure and reduce the amount of water returning to the tank just enough for the siphon to keep up. Its the opposite for a true BA, but hey, it should work! of course... if what you are saying is the flow from (pipe 1 in your diagram) your overflow is too fast, maybe try a reducing coupling or something similar.

Best of luck