Is a overflow box necessary?

rigelstar

New member
I am drilling the back of my tank for 2-2" bulkheads for a closed loop fed by a dart pump and 2-1" overflows for my sump this weekend and would like to know if simply using bulkhead screens is ok instead of using a overflow box.

Thanks
 
yes its fine as long as your sump can handle the ammount of water that will drain. it will drian to the bottom of the baskets so make the as high as possible.

you wont get very good surface skiming with out the box tho
 
<a href=showthread.php?s=&postid=14475559#post14475559 target=_blank>Originally posted</a> by java
yes its fine as long as your sump can handle the ammount of water that will drain. it will drian to the bottom of the baskets so make the as high as possible.

you wont get very good surface skiming with out the box tho

I am planning on putting the 2-1" overflows for the sump at the top left and right corners about 2 inches from the top. The 2-1" overflows should only be ~ 600GPH for the sump. That shouldn't be too much for the sump. The 2-2" overflows for the closed loop will be 3/4 of the way up the tank about 10 inches apart. I am going to have 8 1/2 inch nozzles on the manifold (3 front, 3 back, one on each side) of the closed loop and will use the two nozzles on the left and right side for surface movement.

Is there anything I am overlooking with this setup? I built the sump(40 gallon breader) last weekend and am very eager to test it out. The sump has two bubble traps one between the overflow/fuge section and one between the fuge/return section. Was a thrill to build. The wife painted the back of the 120 tonight and it looks wonderful.

Any insights in this build would be much appreciated.
 
if the power goes out the closed loop will drian that 1/4 of the tank's water down into the sump. this could be not fun
 
<a href=showthread.php?s=&postid=14475890#post14475890 target=_blank>Originally posted</a> by java
if the power goes out the closed loop will drian that 1/4 of the tank's water down into the sump. this could be not fun

The closed loop is not connected to the sump. It is a closed loop. The 2-2" overflow will T- into the dart pump which will return to the manifold. Its a closed loop. The sump will have a separate return pump that will feed a 1" return behind the live rock.

I am hoping for 1800-2400GPH from the closed loop and 300-600GPH from the sump return.
 
you dont *need* an overflow box... go to lowe's or HD and get 2- 1"x2" bushings and 2- 2" 90* ells.... works great
 
can't for the life of me find the thread i saw this in, but thought about doing it instead of my glass-holes.com overflow box. in the link someone had also done it w/ a slit cut w/ a bandsaw instead of the drilled holes....i think either would work rather well

**edit** found the thread :)
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1257783

overflow.jpg
 
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i advise a ball valve on return but never throttle back your drain(overflow).
you can control water flow by adjusting return valve.even if you have a pump thats rated for higher gph than what your overflow can handle you can throttle it back until they even out.
 
I would rethink your drain plans. You NEED surface skimming.

I would rethink your closed loop plans as well. 8 outlets IMO is too many. It will more than likely drop the flow coming out each outlet to the point that it is not enough flow to do the job you need it to do.

I have a closed loop fed by a dart on a 150 tank. It's hooked up to an OM 4-way so it is only coming out of 2 outlets at any given time and seems to be OK. Still wasn't enough for for the entire tank and so I added a couple of Tunze pumps but that's another story. The point is that you won't be happy with the flow from a dart being divided 8 ways.
 
I must agree about the need for surface skimming. I think you should do a little more research and get more input on the problems you may encounter without some type surface skimming overflow. ;)
 
Assuming common dimensions, when you lose power you will drain approximately 10.5 gallons from the display into the sump.

(inside dims):
71" x 17" x 2" = 2414 cu in / 231 = 10.45 gal

So as long as you operate your sump (40 gal) around the 20 gal level, an extra 10.5 gal will not cause an overflow.

Todd
 
This setup would give a degree of surface skimming and possibly as much as an overflow. While the overflows have more lineal footage this setup would have a much greater flow in a single area so it would pull with much greater velocity.

That aside, I don't like this idea for the same reason. An overflow, by not concentrating the water movement to a small area won't pull fish, inverts, plants, etc over too easily whereas this thing will have quite a bit more force. Ever have something stuck to the intake of an in-tank power head or power filter hanging on the back? Same idea.

Why not build a simple box along the top of the back or a side? You only need a few inches of depth so it wouldn't show too much, especially if you used something like black acrylic or similar and wouldn't be a time or money consuming project.
 
A single bulkhead screen skims the surface of my nano just fine.

It actually pulls the food from the other side of the tank a little too quickly sometimes.

smangos
 
I just drilled mine for 2, 1 inch bulkheads. I put 90 degree elbows on them. they are about a 1/2 inch from the surface. I tilted them a little and they are dead silent. They suck tons of water while creating a vortex at the surface. I am using a sceen around them to keep fishies safe.
 
<a href=showthread.php?s=&postid=14479762#post14479762 target=_blank>Originally posted</a> by fishysteve
A single bulkhead screen skims the surface of my nano just fine.

It actually pulls the food from the other side of the tank a little too quickly sometimes.

Great set-up - that is precisely what I will use. I will put all 4 bulkheads at the top and set them up with screens on 90 degree pvc about a 1/2" from the surface. Each 2" bulkhead will provide 6.3 inches of surface skimming while each 1" will provide 3.1 inches. That will provide a total of 18.8 inches of surface skimming. Not bad on a 48" long tank (48x24x24).

The two side returns will also be agitating the surface, provided I get enough flow from my dart. I am going to use flex pvc for the return to minimize head loss. I'll use 1.5" flex -> 1.0" flex -> 3/4" rigid pvc manifold to produce greater acceleration from the jets of the manifold as well. From reading above I will most likely use 6 1/2" nozzles instead of 8 1/2". Possibly, the poster that was only able to use 3 nozzles with a dart pump was using 3/4" nozzles? Let me know if that was the case. I might need a larger pump if you were using 1/2".
 
<a href=showthread.php?s=&postid=14476918#post14476918 target=_blank>Originally posted</a> by james3370
can't for the life of me find the thread i saw this in, but thought about doing it instead of my glass-holes.com overflow box. in the link someone had also done it w/ a slit cut w/ a bandsaw instead of the drilled holes....i think either would work rather well

**edit** found the thread :)


Definitely, a sound looking setup. I don't see why it would not work. The GPH may be diminished but it should work. It would make a great surface skimmer for sump overflow while using a closed loop for most of the tank flow.
 
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