Overflow box not siphoning
 

I've took the plunge and put together a sump in my 65gallon system about 3 months ago and all has been working without issue. I purchased a black acrylic Overflow box (some people call it the weir overflow) and a line connected to the SEIO 820 for suction. This drained into the sump.

Tonite I noticed my water level was very high so I turned off the power to the return and powerhead and turned things back on - this time nothing was draining into the sump!

I took the hose from the box off and tested for suction pressure - still there - then proceed to take the box off the tank to inspect for any clogged pieces.. I didn't have that thin of a brush so I couldn't do a thorough clean inside of it - but have tested that water can travel all the way through by filling one side and tipping upside down to have it travel the path.

I have even gone to putting the overflow on backwards at the front of my tank with no hose connected at the drain just because I'm sure it's not going to start the siphon.

I'm starting to panic a bit here - have moved a heater into the display - and need to fish out an urchin from my refugium for the next little bit until I can sort this out. Can anyone provide any advice as to what I can do?

Completely Baffled!

IMHO I think you should go back to the way you had it 3 months ago until you can invest in and set up a drilled tank. Don't even bother with a siphon overflow.
I learned my lesson with siphon overflow boxes 9 months ago.
Didn't have a flood but I could see one comin'. Not worth the risk.
Got a drilled tank now and it is waaaaaaaaayyyyyy better.
Maybe not the answer your lookin' for, but that's my humble opinion on it.

Cheers,:smile:

Is this overflow a u-tube design? Is your SEIO 820 for sucking out air in the top of the u-tube?

If it is a u-tube, are you priming it? Are both ends of the u-tube submerged in water when power goes out? My guess is your u-tube has broken siphon, you need to prime it, and make sure both ends stay submerged when you power goes out, this is easy to test.

Johnny, can you explain why your overflow almost flooded? I just dont want to scare people away from them without knowing why. External overflow boxes can be setup completely flood-proof IME, but most people do not take the necessary precautions, the devices are as safe as they are setup and maintained.

The overflow is not a Utube design - it is more like a "Calfo" style or "Weir" style with various baffles inside of it. It has worked flawlessly for 3 months without any issue - which is why there is a big concern with me..

Unfortunately just going back to the way it was is not an option - I woke up this morning to find my fish gasping at the water for oxygen - due to the lack of movement from just the two powerheads. I have thrown an airstone and a couple more powerheads towards the surface for now until I can get home from work. I will have to find a way to get the skimmer to work if this is going to be more than a couple days - either way this is frustrating!

The SEIO powerhead is constantly connected to the air nipple sucking from the top which is how I get the siphon to start in the first place..

Any other thoughts would be appreciated..

Does it look like this? Is the siphon breaking? Maybe you have a slow leak in it, enough that when the power goes out it leaks and loses siphon?

http://www.melevsreef.com/29g/sump/weir.jpg

Yes looks very similar to that.

I have taken the box right off and attempted to start the siphon all over again with no such luck. It doesn't LOOK like there are any leaks or holes in the acrylic and I can hear a sucking sound when the hose is attached to the top nipple of the box to suck air out.

I think I may be able to get a utube type box today for testing and will see how it goes - but the fact of the matter is - this doesn't make any sense at all - It wont even start sucking from the "inside of tank" part of the box :(

.. and everything was going so good lately..

Maybe your Seio pump is broken?

Try taking a line of 1/4" airline tubing, and fishing it into the middle, and sucking air out yourself to prime the overflow. This is how I started my u-tube overflow.

It didn't almost flood. I said I could see one comin'...meaning if I kept with the siphon overflows I envisioned a flood in the future.
Started with two overflow boxes, one U-tube in each. Did a test to see what would happen if one U-tube lost siphon. Test failed. The one siphon left couldn't keep up with the return. So, I doubled up the U-tubes. Two in each box. But then there was too much distribution and one U-tube would lose siphon over a long period of time, leaving only three doing the job. One day I noticed salt creep on the plumbing to the sump. So I shut the pumping down to silicone the plumbing joints. My sump slooooooowly continued to fill with water. Turned out water was being siphoned out into the sump through the powerhead's airline tubings. Oh ya? So how do I stop this? Check valves in the airline tubing. So I went out and bought a bunch of check valves. But I never installed them. I decided @*^%$# this. Shut the sump down, went back to a canister filter and pressed on as before until I could afford a drilled tank.
I should qualify this by saying that part of my decision was the fact that I worked away from home for long periods around that time. But still, wether one is working 500 miles away or 5 blocks away, a flood is a flood. You just find out about it sooner if you are 5 blocks away. JMHO.

Cheers,:smile:

So after my boss sent me home early today to take care of the mess I was about to deal with - I came in and noticed why my fish were gasping for air this morning, I only had one powerhead going all night due to my mucking around to see if the powerheads were broken (to answer the above question). The airstone and extra powerheads I threw in before going to work helped alot, all livestock was alive.

I decided to give it a whirl again today and everything worked as planned without issues! I just don't understand what the heck is going on here. Mind you - I don't trust it. Looking for a 65gallon tank to drill and then will sell this one.

The saga continues.

If a u-tube loses siphon, it just means that your pump in your return section of the sump will continue pumping water into your display.

This is not good, but not that bad either, as long as you have measured the additional capacity of your tank, and not built your return section larger than that.

In this case, all that will happen is your pump will run dry, but no flood. To solve this, use a float switch set to turn the pump off if the water level drops too low. Add a second as back-up, and there should be no way to flood.