Overflow/Sump question

[gradoj]

I am new to reefing and am trying to setting up a tank about 30g. I am getting the tank custom made and am trying to figure out the whole sump/overflow business.

1.I do NOT want to put an overflow box into my aquarium. What is wrong with just getting the hole drilled near the top and connecting a 90 degree connector to the bulkhead? The overflow will just be the 90 degree connector itself. Am I missing something here?


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2.Can I use one of those SCWD units as a return from my sump?

3.If I do what I discussed above I need to get 3 holes drilled in the back of my tank. 1 for the overflow and 2 for the returns. What size of pipe/holes/bulkheads should I use for each?

 

[Entropy]

1. You can do it but it generally is not as reliable and does not drain as good (lower gph).

2. yes

3. Just one, you can return the SCWD over the back of the tank (unless you really want it to go through the back).

 

[reefwick]

Alot of people get their tanks drilled. I'm not an expert in this area but an over flow will take the very top water off, with all the oraganics, straight to your skimmer for more effiecent skimming. The drilling is more for closed loop set-ups. I'm sure you could have a hole drilled to go to your sump but you may get a film on the surface of the water.

Yes you can use a SCWD for your return butmight want to look into a closed loop though.

As far as sizes I have no idea. Might want to try the lighting, filtration and other equipment forum or the DIY forum for that answer.

 

[gradoj]

<a href=showthread.php?s=&postid=6595016#post6595016 target=_blank>Originally posted</a> by Entropy
1. You can do it but it generally is not as reliable and does not drain as good (lower gph).

What kind of flow rate is recommended from main tank to sump and back?

 

[dchao]

Most people do 3-4x the turnover of the tank size to the sump and skimmer. The rest of the flow is supported by close loop (or PH's). There is no need to take all the water to the sump and pump it back *up* to the display (electricity bill $$$). Close loop pump does not use as much electricity.

 

[Palancar]

I researched this once before and I think it was determined not to be a good idea. An open drain pipe like that will be noisy. So you would want a standpipe top for it at least. But that means the water will be pulled from below the surface. Which means no more surface skimming.

 

[dchao]

A Durso standpipe normally sits inside the overflow box, where the only surface water can enter. The surface skimming is actually being filtered by the slots on the overflow box, the standpipe is only there to reduce water noise.

 

[gradoj]

If I do use a SCWD on the return from the sump would that give enough flow for the tank? or would people recommend another closed loop system or powerheads in the tank?

Or should I just use 1 return line from the sump and a closed loop system with a SCWD?

Maybe I should ask it this way:
If you were starting a 30g tank from scratch what holes would you get drilled in the tank?

eg. 1 for the overflow and 1 for the return? 2 for the overflow(one in each corner) and 1 for the return? 1 for overflow, 1 for return and 3 for closed loop?

I would like to not have any powerheads in the tank. But still want very good flow. Any advice appreciated.

 

[dchao]

I would drill one for the overflow and one for the intake of the close-loop. If you drill 4 holes, you are risking weakening the tank.

 

[AllenFord_SC]

Ok the pipe idea is really not a good idea. As someone mentioned earlier the overflows main objective is surface skimming, removing a protein slick from the surface of the water. Without proper surface skimming, you are not getting a good gas exchange rate resulting in less oxygen in the water leading to unhealthy fish. As unnatractive as they are, overflows are the best way to go. To figure out your pipe/bulkhead size needed you need to first figure out how much flow you want. You have a 30gallon tank so I would shoot for around 120 GPH. Next figure out your head loss, how high the pump needs to lift the water to return it, and find a pump that matches your needs. Once you find the pump, the manufacturers usually have a recomended pipe size for the particular pump. If not, just match the pipe to the intake/return of the pump. I would recommend the Mag 2 because it pumps 125GPH @ 4ft. head loss. Inexspensive pump that can be used in the sump or as an external.

Hope this helps.

 

[unsane]

<a href=showthread.php?s=&postid=6595784#post6595784 target=_blank>Originally posted</a> by dchao
Most people do 3-4x the turnover of the tank size to the sump and skimmer. The rest of the flow is supported by close loop (or PH's). There is no need to take all the water to the sump and pump it back *up* to the display (electricity bill $$$). Close loop pump does not use as much electricity.

I am trying to figure out how a closed loop and a sump return pump is cheaper on the wallet then just draining to the sump and returning to the display? 2 pumps running versus 1 pump running.

 

[AllenFord_SC]

Ok, The 1 pump vs. 2 pumps arguement. While it seems like it would cost more it actually is about the same if not less to run a second pump on a closed loop. Here is why. If you are running 1 pump as your return you will need more flow. To compensate for this lack of flow people either get a bigger pump (more money and more electricity) or use powerheads (also more money and electricity). Plus powerheads are not attractive and with all the added heat may eventually require you to get a chiller (huge amounts of electricity). One the other hand, you can get a small return pump like the Mag 2 (24W to run) and add a Closed loop pump to supplement your flow needs. These external pumps use little electricity and are virtually invisble as far as added heat.

 

[dchao]

The main reason the close-loop is more efficient has to do with the head-loss. There is no lead-loss with a close-loop, but to pump water up from the sump to display (4-5 feet) will loss 40% power, this energy is wasted. That's why you don't want to push too much water into the sump, too much over the skimmer's rating.