Prevention of sump overflow during power cut?

[Norge]

My situation:
I have a custom built acrylic tank, with a built-in sump in the stand. When there is a power cut, the return pump stops, duh, and the water flows reversely back into the sump. The problem is that approximately 5-6 gallons run back, while the sump only holds 3-4 gallons.
Well, this has happened while I was at work, and the result is that I loose so much water that the circulation stops and the sump runs dry. This has made my rio on my skimmer to burn. (Luckily, my room-mates heard the noise and turned everything off, phew! :D)

Is there any way to safely prevent the reverse flow during power cut? Couldn't I use a check valve, or would this get clogged?

I know you guys have an answer to this problem, so I hope you would like to share it with me :)

Thanks,
Thomas

[Rovert]

Norge, raise the return nozzle higher in the tank, so that if the water level drops 'x' distance, that it only accounts for the volume of water your sump can handle. If you put that same return nozzle at the bottom of the tank, it would siphon the whole damned thing onto your floor, so the opposite concept applies here. Higher=less where this siphon idea is concerned.

That, at least, is the easy solution. You can always start attaching other gizmos as needed, but if they fail...

I tend to feel that the laws of physics are the safest guarantee, since they don't break, like a check valve can. :D

[Norge]

Thanks for the reply Rovert.

I know my physics :D (engineering student), but I forgot to mention that the return nozzle is a "built-in" nozzle that cannot be adjusted :(

If I want to raise it, I would have to replumb the return, which I really don't want to do... Isn't there another way?
Some sort of failproof check valve :D ?

[jgarris11]

DRILL A 1/8" HOLE ABOUT 1/4" BELOW THE SURFACE OF THE WATER. THAT WAY WHEN THE WATER LEVEL DROPS IT WILL SUCK AIR AND BREAK SIPHON.



JIMMY

[Norge]

Thanks for the tip, Jimmy!!!
Talking about a simple and cheap solution to my problem!!! :D

[cwa46]

Don't forget to clean the 1/8 " hole "every" week. IT will fill up with salt, algae, and sometimes even a snail will cover it.

[johnny]

I'll disagree with putting the hole BENEATH the water... put the hole ABOVE the waterline. Then you don't have to worry about snails covering it or coraline covering it... also the water flowing out of the hole should help to keep it from clogging.

Nick

[jgarris11]

IF YOU PUT THE HOLE ABOVE THE WATER LINE THEN YOU HAVE A FINE JET OF WATER SPLASHING AND PUTING BUBBLES IN THE TANK. ALSO SNAILS WILL CLIMB OUT OF THE WATER ON OCCASIONS WHEN THE ARE CLIMBING ON POWERHEADS AND RETURNS SO THEY MIGHT STILL CLOG THE HOLE OUT OF THE WATER. EVEN THOUGH IT IS UNDERWATER, WATER WILL STILL BE COMING OUT OF THE HOLE.


JIMMY

[Clyde]

or get a bigger sump

i'm setting up a new 180, I m getting the largest sump I can get.
so far, i have a 42 gallon long set up for it.

[Playfair]

How full is your sump running? The only GUARANTEED way to prevent over flow is to make sure the sump can handle all the water that comes back to it. I have a 20gal sump, but only run it 1/2 full so that the second half can absorb the excess 8 gals tank water that will come down there if the return stops...

[KASESQ]

And you will need to get a little brush to keep that
hole clean-algae and dried salt will clog it otherwise in short order and the return will back siphon anyway if power is cut off.

[Theo]

Hi Norge, just thought I'd throw my solution in. I took an old aqua clear filtre box placed it on the back of the tank like normal and put my return pipes in there. That way in case of a power outage it can only back siphon the amount in the box. This is a very small amount of water and there is less for the live stock to tamper with.

Cheers
Joe

[johnny]

AS LONG AS YOU HAVE THE HOLE LOW ENOUGH YOU SHOULDN'T HAVE TO WORRY ABOUT THE WATERJET/BUBBLES... IF YOU'RE THAT WORRIED ADD SOME TUBING THAT JUST BARELY REACHES THE WATER...

I agree it should be cleaned still and snails still can get onto it, but the time it would take for algae/salt creep to clog up is greater and chances of a snail being there at just the right time is pretty small in comparison to if it were inside the tank. If you can put the hole where the return line goes over the overflow, so that the water that sprays out of the hole jsut goes into your overflow, that would be best, then you wouldn't have to worry about anything other than saltcreep and since there will be constant flow through it, that would be much of a worry.

Nick

[Norge]

Hi everybody!

As mentioned, the problem is that the tank is a custom made acrylic tank with an acrylic stand. The sump would only hold about 3-4 gallons, and if I want to expand that, I would have to put a new sump on the floor besides the tank. Here is a schematic of the tank:
http://www.tc.umn.edu/~kjos0017/images/tank.gif

Since the doors in the stand restrict the amount of water I can put in the sump and that I want the setup to look pretty, I would have to build a new stand in order to put in a bigger sump. This is not an option I like, cause then I would probably upgrade the tank while I'm at it, and I would probably buy more lights, perhaps some more LR, hmmm lets get an even bigger tank, etc. etc. :D
That could be rather expensive :)

All in all, I have relatively limited options if I don't want to drill in the tank, build a new stand, or replumb :(

Theo:
Could you give me a schematic on how you have done that Aquaclear box? If it's an hang-on solution, I could not use that...

Thanks everybody, and keep the solutions coming :D

Thomas

[Norge]

I could add, that I think that the hole above the water line would be a good solution.
As to whether a snail would clog up the hole, I think that the water flow would be too high for it to settle down there :D, or at least hope so...

Thomas

[Agu]

Norge,

Replumb the return, or accept the inevitable fact that you will have floods. Siphon holes will work most of the time, but they're not foolproof. Check valves fail. To my knowledge no one has repealed the laws of physics ;).

You might consider adding an extension to the return that raises the outlet instead of replumbing the whole thing. Something like the loc line shown here.
https://secure.voyagerhosting.com/savko/loc.html


fwiw,imho,etc...

Agu

[Norge]

Thanks Agu!

Didn't you know that I'm a Laws-of-physics-defying-super-hero? No laws of physics affect me :D

But seriously, I guess just changing the return nozzle would be an option. I will be moving in a weeks time, so I could try then. By the way, do you know anywhere here in the Twin Cities where I can buy the loc line or similar?

[Agu]

An LFS or mail order place should have it. I believe Premium Aquatics (plug the sponsor ;)) carries it.

Agu

[SohalTang]

What's wrong with check valve ? I have had check valve for years and it works wonder. Drilling the holes in the return line wont work because usually the return nozzle is under the waterline in most acrylic aquarium with built in overflow. Just make sure you buy the all plastic checkvalve.

[G7subs]

If you decide to go the check valve route be sure you use a swing check, and install it so that it is easily removed.Make it part of your maintanence routine to take it out and clean it.Also every once in a while test it by turning off your return pump and see if the sump level rises.