Flow Division

[RichConley]

I'm in the process of setting up and plumbing a 20L. I've got a 10 gallon tank as a sump. With my reading, I figured 250 gph would be good turn over, its 12.5x the tank volume. I did some math, and figured with 4' of head, I'd have 279 gph from a mag 5. Sounds good to me.

So here's my question: Should all 250+ gph of flow come from the sump return, or should I go with a much smaller pump, say 100gph, and use something else for circulation?

I'd like to keep the inside of the tank as clean of equipment as possible, so I dont want powerheads hanging all over the place.

Does it really matter?

I was just looking at a big reef (320g) and he had about 6000 gph of turnover in the tank, but only about 200 gph from the sump and back.


Would I be putting too much water through my sump if i ran the mag5?


what do you guys think?

 

[dedfish]

I have a 20L with a mag5 about 2.5 feet below the tank. I don't have a sump, just a closed loop. The configuration I am running now is a mag5, up about 2.5 feet to a T and then plumbed through the back of the tank. Inside the tank I have the Hydor devices to switch up the flow. I like it. I think I could stand a bit more though. I used to have a mag7 with a SCWD on this tank and the flow was about the same as the mag5 without the SCWD. I don't think a mag5 would be too much and I would definetly consider something bigger if your planning on restricting the flow at all with a SCWD or some other device.

 

[RichConley]

would putting a spraybar or splitting the mag 5 into multiple output nozzles be a good idea to make the flow more...I dunno....spread out?

Also, what is the point of having a closed loop without a scwd or other current...rotater?

Also, where is the best place to have current coming from? I'm going to have my overflow in the center rear of the tank. Should i have the outlet nozzles in the back bottom corners, back top corners, what am I trying to do here?

 

[jango]

would putting a spraybar or splitting the mag 5 into multiple output nozzles be a good idea to make the flow more...I dunno....spread out?

It would spread it out more but would also cut it down...

 

[dedfish]

I have a closed loop because at the time I set up the tank originally I couldn't have a sump. I do however have a large refugium that sits behind the tank. The Hydor devices are current rotators.

If you used a spraybar I would definetly step up a size with the pump. A spraybar will restrict the flow a bit.

 

[RichConley]

How much do those things run, and where can I find them (hydor)?

Would I need to step up to the Mag 7 at this point? or should I just look at plumbing in a 2nd pump and running these on a closed loop?

I guess my main question is this: Is it better to up the flow to/thru/from the sump, or to add powerheads to the system.

Rich

 

[dedfish]

The Hydor devices can be bought from a variety of places. I got mine from a friend who I think bought them online.

The mag7 might be too much for the hydors depending on your plumbing. They are rated for up to 310gph.

The question of flow to/thru/from sump vs powerheads depends on a lot of things. How are you getting the water to the sump? How much flow can your overflow handle? I know it's tough with a 20L when your trying to keep it clean, there is not a lot of space and your constantly battling with ideas. One thing to keep in mind is if you use just 1 pump then what happens if it fails. Maybe go with the mag5 in the sump and some small powerhead in the tank for added flow and backup.

Here is a link to my photo gallery of my tank. There are some plumbing pictures in there, but I don't think there is any with the hydor. It may give you some ideas.

 

[RichConley]

Theres nothing in the tank yet. I am just starting, and want to do it right the first time.
Was thinking of using a 1" bulkhead for the overflow to drain to the sump.

So I really have no "I've already got this in" constraints.

 

[kurt448]

What are you planning to put into the tank? If you are going to have SPS I would highly recomend a pump with a much higher flow rate. If you are just doing softies a mag 7 would probably be good as your only flow source if through a SCWD.

 

[RichConley]

really? With a mag 7 I'm looking at 460 gph at 4 feet of head. That seems absurd to me for a 20L. It also seems like putting 460gph through my 10g (probably about 5 -7 full) sump is scary. Should I just go with a mag3 or something for the sump, and put in a seperate closed loop, or what?

Will 450 gph through the sump do bad things to the fuge (which gets about 1/2 the flow)?

 

[denvig]

I think the pump and rate through your sump is fine. I would however add one small (MaxiJet 400) power head within the tank opposite to the returns to add some random flow patterns to the tank.

 

[nunofs]

450gph in a small fuge sounds too high... you may want to add a ball valve where you split the tubing so that you can better adjust the flow that actually goes through the fuge.

I have to agree with your wish to avoid powerheads in the tank, they tend to take up a lot of space (relatively) and look very conspicuous especially in a small tank. I think I'd go with a less powerful pump for the sump return, and then add a closed-loop just for flow (drilled or over-the-back, doesn't really matter in terms of flow -- you get additional adjustability if you do it over-the-back, and possibly a better-looking solution if you drill)

Nuno

 

[NateHanson]

Also, where is the best place to have current coming from? I'm going to have my overflow in the center rear of the tank. Should i have the outlet nozzles in the back bottom corners, back top corners, what am I trying to do here?

If you're talking about your return nozzles from the sump, you have to keep them near the surface. If the return pump stops (power outage, etc) then the display tank will siphon back into the sump through the return plumbing until the water level drops below the opening of the return nozzle. So you should keep your return nozzle within a 1/4 of the surface.

Closed loop won't back-siphon anywhere, so you can drill those returns anywhere you like.

 

[RichConley]

Are there any negatives to a closed loop? Is a scwd worth it?

 

[kurt448]

Rich, what are you planning on putting in the tank first of all??

I have a 16 gallon(only 20" long) SPS tank with a Mag 7 running through a SCWD. I lose a lot of pressure due to the SCWD and even need a separate mini jet to minimize dead spots. Even with that I still could use a lot more flow.

In my opinion a closed loop might be ideal for your tank. If you have large(3/4" or larger) outlets for the closed loop this could give you a strong laminar but not turbulent flow. Hope this helps...but really it all depends on what you plan to put in the tank in the future.