Building a sump

wake49

I am beginning to build my sump, and do not have a reef-ready tank. So this means I will require a external overflow. I see that all these skimmer boxes come siphon ready, but do any come pump ready? Is there a reason that I cannot find one that will pump water from the skimmerbox to the external overflow? It seems to me that a setup like this would be less likely to fail, without the risk of a siphon break and all...

Maybe if one doesn't exist for sale, suggestions on what to use to build my own would be appreciated.

SKAustin

Im not sure I follow your question here. By skimmer box, are you referring to the portion of the external overflow that sits inside of the tank and effectively surface skims the water?

Have you read the sticky on Understanding Sumps? I believe there is a section in there that covers the External Overflow.

http://www.fishforum.com/viewtopic.php?t=18777

wake49

I have read that article a few times now. It is very detailed and has helped with all the basic questions I had to get this thing started.

I am taliking about the Prefilter, as it is referred to in the article. My LFS guy calls it a skimmerbox. I want to pump water from inside the tank portion of the prefilter to the external portion of the prefilter. I don't trust a siphon. I have thought of dismantling a whisper HOB filter, and using the impeller and main tube to force the water over the back wall of the tank.

I included a picture from the article that I labeled to hopefully clarify the idea.

wake49

Here is the pic

SKAustin

I see your issue now. Let me start by saying I run an external overflow on one of my systems, and have never had issues with the siphon breaking in the U-tube. As long as the flow in the u-tube is strong enough for any bubbles that enter to be carried all the way through the tube, there is little chance you will ever have a problem. They are really a lot more reliable than they may seem. There is however, an alternative to relying solely on the siphon, and that is to have a small water pump drawing water through a port in the top of the U-tube out, and back into the inner portion of the overflow unit. You can earch Ebay to find examples of these units.

Another idea is to buy yourself a reef ready tank, or if your tank is not made of tempered glass, have it drilled and build your own reef ready setup.

Personally, i think the idea you are entertaining is a recipe for disaster. If the pump output from your return line does not match the output from the pump you install in the overflow EXACTLY, you will end up with a flood. To install identically rated pumps would not suffice as the back pressure from gravity would slow the return line reducing the total GPH. Regardless even the difference of 1 cubic centimeter per day would eventually result in an eventual flood.

wake49

Thanks for the feedback.
I thought it could be a disaster, so I was going to install flow valves on each pump.
I like the idea of installing an air lifter to keep the siphon continuous, though. I found this on Dr. Foster & Smith, and think I can create something similiar.


Would a standard air pump help keep the siphon continuous?

SKAustin

No. You need a water pump. An air pump would cause the syphon break.

Personally I still think this is unnecessary. As I said, as long as you have the proper flow, and the overflow box is designed properly, there is little chance you would ever experience a problem with siphon break. But you do what makes you comfortable. If the pump gives you the piece of mind, then it's worth it in my book. :) Good Luck.

wake49

I will try it as just a siphon for now. As long as that treats me fine, I will keep it that way. You sound like you trust it, so why not? I am going to get the prefilter and 15 gallon tank tommorow. What do you suggest for plumbing the sump? Is there anything I should know about pumps and such?

SKAustin

What are the details for your system?

wake49

46 Gallon Bowfront. 1 Powerhead, I think it is a Koralia 3. Right now I am running a Fluval 305 canister filter. I have a stealth heater, keeping the system at 75-78 degrees. The tank is about 32" from the ground, and has a cabinet stand. I am picking up the fifteen gallon tonight. I was going to use a twenty, but it was too big to fit under the cabinet.