Dual Sumps

[MLab]

First time poster, long time reader.

I used to have a reef a few years ago; as I could not afford much, I went with a nano reef which seemed to be a decent budget aquarium to start with. Surprisingly enough, it ended up doing well even with my inexperience. In the end, I sold everything as I had to move and found that such a small aquarium left little room for expansion and that frustrated me.

Fast forward to today, I’ve been obsessively reading about reefs for the past month or so, slowly getting back into the hobby. As I used to have nano-cube where everything was already set up, there are a lot of concepts that are new to me (sumps, skimmers, overflows, refugiums, types of light to use, etc.) so I’m slowly starting to understand the different concepts behind everything. That said, pardon my lack of technical jargon; this is all very new to me.

I’m slowly purchasing my equipment and I bought my aquarium and stand earlier this week. It is a Fluval Osaka 320 tank (70 gal.). It’s one hell of a nice tank, decent size, very sleek look, etc. I’ve read about it a bit but could not find much info; General criticism was that the build quality of the aquarium wasn’t so good. From what I've seen, it looks mighty fine to me but, honestly, it's my first big aquarium so I guess my knowledge is pretty limited.

My only problem is the stand it came with. It’s divided into 3 parts:

-14.5w" x 17.5l" x 23h" left area, closed by a cabinet door
-Front area, open
-14.5w" x 17.5l" x 23h" right area, closed by a cabinet door

My first idea was to just put a 20 gal. DIY sump/skimmer/fuge on a stand behind the tank (linked by an external overflow; I do not want to drill my main tank). This would obviously be the easiest solution to implement.

But since I am not really pressed for time, an idea came to my head and I was wondering if I could have some sort of "double sump system" where I have 2 x 10 gal. tanks. One enclosed in the left cabinet and the other in the right one.

I’ve taken measurements and the tanks would fit in without a problem although they’d be a little too long for the left/right areas (tank size is 19.5" x 11"). But that doesn’t worry me as I can cut around the very thin back panel to give an extra 2 inches of space.

-'Tank A' would hold my skimmer (Aqua C Urchin Pro) and get the water from the overflow.
-'Tank B' would be my refugium and where my return pump would be.

Both tanks would be drilled and linked through PVC tubing. The distance between both sumps would probably be 24" to 30".

So my main questions are as follow:

1- Does my double-sump idea make sense?
2- Anything I should take into account that I didn’t seem to?
3- To get the water to go from Tank A to Tank B, should I get a small pump or will physics work its magic and get the water to tank B without a problem?
4- Any better suggestion considering my limited space?

I’ve included a picture of what the stand looks like and of what my plan is so that you all can picture it better.

 

[coralfragger101]

You definately DO NOT want to use a pump to get water from sump A to sump B. You definately DO want physics to manage this feat by itself.

You just need to make sure that the pipe connecting the two will be sufficient to handle the flow between the two sumps. There are no calculators for this that I am aware of. The normal drain calculators will not work for this application because pipes running horizontally versus pipes running vertically will not drain or act the same.

 

[sjm817]

[welcome]

Honestly, I would consider a different stand. That one is not designed to be "sump friendly". Once you fill the tank, you will have to live with it.

 

[Percula9]

Just as long as the return pump is working water will flow from one tank to the other. I've seen this done before with no problems. Can you modify the stand to accept one single 20 to 30 gal sump. I think that would be simpler than two connected tanks.

 

[MLab]

Thanks for the welcome and the answers. I realize the stand is not ideal but the reason I got this tank is partly because of its stand which I find integrates well with everything else that I own. I am willing to live without the practicality of a custom made stand but I am just trying to make the most out of it.

I have enough room behind the tank/stand to put a normal 20 gal. sump without it looking too out of place, but I'd rather go for a more "integrated" look, if at all possible and I believe it is. At least, it makes for an interesting project.

<a href=showthread.php?s=&postid=12881485#post12881485 target=_blank>Originally posted</a> by Percula9
Just as long as the return pump is working water will flow from one tank to the other. I've seen this done before with no problems. Can you modify the stand to accept one single 20 to 30 gal sump. I think that would be simpler than two connected tanks.

There's probably a way that I could modify it but I really am not comfortable enough with woodworking/carpentry to tackle this while doing a good, clean job.

 

[areze]

raise 1 up. use 1 as a sump. then place a pump to pump water to the other tank(the refuge), and put an overflow on the refuge to drain water back to the sump.

that will let you manage the flow through your fuge as well. plus you can disconnect it from the system should you need to. just raise the fuge tank up a few inches, as much as you can anyway. and you should be all set.

 

[seaskraP]

^ +1

 

[FLAZ28]

i have a double sump system works awsome.......main tank over flows into refugium................and from refugium to return sump ...........work great

 

[120reeferman]

better way would to elevate the first sump a tad and have it gravity drian into the other sump via a bulked in the side of it....then no worries when the power goes out

 

[kcress]

You do not want a pump as stated previously by coralfragger101. That is a disaster waiting to happen!

Just plumb in the largest cross pipe you can. Do not go over board on the fuge sump flow rate.

Put in a valve in the return to the tank. Throttle the return to prevent a large height difference between the two fuges.

Tank will flow to fuge 1.
Flow will occur to fuge 2 via connecting pipe.
A pump with a return valve will draw from fuge 2 and pump back to the tank.

The flow between fuge 1 and 2 will be created by a pressure difference between the two sumps. This difference will be due to height differences. Fuge 1 will have a higher level than fuge 2 or no flow will occur. The greater the flow the greater the height difference. The larger the cross pipe the greater the flow at any particular height difference.

When you turn on the pump as it draws down the fuge 2 level, flow will start from fuge 1. The higher the flow the greater the height difference will be.

If you had a really large pump or a really small connector tube you could have fuge 1 (F1) be nearly full and F2 nearly empty to have it all work. You, of course, want to avoid this.

If you can tell us how big the cross pipe shall be we can probably tell you how much flow a 1 inch difference in heights would represent.

 

[coralfragger101]

<a href=showthread.php?s=&postid=12884798#post12884798 target=_blank>Originally posted</a> by 120reeferman
better way would to elevate the first sump a tad and have it gravity drian into the other sump via a bulked in the side of it....then no worries when the power goes out

Elevating one and using gravity to drain into the other will have no effect whatsoever as to what happens when the power goes out. Whether you keep the sumps the same level or raise one you have to insure that you have enough extra "empty" sump space to be able to handle the amount of water that will drain from all areas of your tank when the power goes out - period.

Raising one sump as some of suggested will certainly work. A simple pipe between the two will certainly work. I don't believe anyone can say that one is better than the other. If you are going to be able to view both of these sumps then personally I think that from an aesthetic standpoint that having the sumps at the same level would be more appealing but that is simply a matter of personal preference. As Kcress has suggested, the larger the pipe, the more flow you can achieve between the two sumps. I have a 50 gal sump connected to a 29 gal sump (at the same level). Originally they were connected with 1.5" PVC pipe. It worked fine. When I reworked my sumps I even went bigger. Now the two sumps are connected with a piece of 3" PVC pipe.

 

[kcress]

Hey coralfragger101;
What's the surface height diff between your two?

Have you got any guess at the flow?

 

[coralfragger101]

Unfortunately I'm out of town till tomorrow night so I can't go look at it. I can let you know tomorrow night. If I recall correctly, since I put the 3" pipe the level isn't much different at all. It's also hard to say what my flow rate is as well but I'm sure the flow through the 3" pipe is probably in excess of 2000 gph. I'll see if I can't estimate that a bit closer as well.

 

[seaskraP]

If your going to plumb them together at the same elevation, go big with the pipe.
the sumps i have now are connected with 2 x 1" and they will still get clogged once in a while, and the water level drops significantly in each one at only 600ghp.
gravity is the way to go imo

 

[coralfragger101]

In actuality, gravity is the force being used in both cases.

 

[Bruno3047]

No need to have Fuge 1 higher than Fuge 2. Water always seeks it's own level. As water is pumped out of Fuge 2 into the DT, the pressure of the water in Fuge 1 will naturally cause it to flow into Fuge 2 to make up for the displaced water being pumped into the DT.

It's actually a pretty simple and effective system. Just have to be sure the connecting pipe is large enough. I would guess a 1.5-2" pipe should be more than adequate.

 

[coralfragger101]

<a href=showthread.php?s=&postid=12885199#post12885199 target=_blank>Originally posted</a> by kcress
Hey coralfragger101;
What's the surface height diff between your two?

Have you got any guess at the flow?

This might be good to know if someone else actually wants to try connecting two sumps via a straight pipe.

This is simply a piece of 3" PVC pipe connecting two sumps using 3" uniseals (4" hole). Water levels don't vary by much. Maybe 3/4 of an inch at my current flow rate.

Just for giggles I decided to up the flow and got a surprising result.

The water levels appear to come closer to being level with MORE flow going through the pipe. Explain that one?

The big question is how much flow do I have going through the pipe and unfortunately I can not tell you.

My return pump is a Dart (3600 gph). That's with no head of course. This pump is also delivering water to 4 ball valves. 2 put water into the main display, 2 put water into a frag tank and 1 puts water through reactors for carbon and GFO. The Dart is run wide open but ALL 4 ball valves have some restriction to them. It's anyone's guess as to how much flow is going through the pipe. I have no clue.

 

[kcress]

Thanks coralfragger101. Nice shots. Except that last one is OBNOXIOUS!! I cannot, in any way, explain how greater flow would make the levels closer! The physics don't allow it.

My first guess is that whatever you did to 'increase' flow actually reduced it. It could be you actually shifted down the pump's curve reducing flow, perhaps.

Wait a minute... I offer proof of my theory or reduced flow:
Why would the level of any of your sumps rise if you are pumping out more? Your pump should be shifting more water towards your other tanks.

You either did reduce flow or mixed up the pictures?

 

[coralfragger101]

Hmm - I wasn't going to worry about it but now you have me curious. I'm going to have to do it again to prove/disprove the above photos now. It's just a bit of a hassle tweaking things when I'm done playing. Every ball valve I turn effects ALL other outlets as well as several overflows that are manually adjustable (3 pipe silent, failsafe method of BeanAnimal's).

 

[coralfragger101]

Mlab:
My apologies if you feel this is now a threadjack. That certainly is not my intention. What I'm doing here is on the subject of connecting two sumps together and how they act with different flow rates which is what you are considering doing so I would think you would be interested in the results as well.