ext or int overflows on 10x4x30in?

[AMD30]

hi, i was wondering if any one has external overflows on their acrylic tanks? i am trying to save real estate in my long tank.

what are the drawbacks to having the teeth on my 4ft side of my tank? will it weaken the tank alot?

i want to use 2 waveboxes for my tank also.

or should i just have 2x 1.5 in holes drilled on the side of the 4ft wall and then install my own overflow box?(seen some like this on glass cages tanks)?

i really dont want to have to put a 36in long over flow that sticks out 7in into the tank.

 

[Jar*Head]

If you have the right thickness on your acrylic, you shouldn't have any problem with the ext overflow box. How many gph are you planning to do on your return?

 

[AMD30]

about 2600gph, and its going to e 1in all around. is this sufficient enough to have a 40in long x 8inx 8in overflow box on the outside? about how thick does the overflow box have to be?

 

[AMD30]

oh and can i drill 2in long x 1/2 wide teeth that are seperated by 1/2in each?

there is a guy here who was building his own (96x48x30)in his garage and he is only using 3/4in material i believe with an external overflow box.

 

[Jar*Head]

I don't know how thick the overflow box has to be. But 1/2" should be enough since it doesn't hold much pressure or water. Your tank builder should know what to use. 40x8x8 is pretty big...

 

[AMD30]

cool thx man

 

[Jar*Head]

Are you ordering the tank from the same person we were talking about? IMO, he is kinda rude over the phone but pretty cool guy to deal with. He offered a great deal for large size tank.

 

[AMD30]

no, i am going with a different guy in socal. that other guy jacked up my price quote by 30% because of "price increase of acrylic by 30%" but the guy who is building mine said that was probably BS! lol .

 

[Acrylics]

Personally, I'd use 3/4" for the overflow and would recommend the same though 1/2" would hold. 2 x 1/2" slots would be waaaay more than enough to handle 2600gph but if you're planning on Waveboxes, then it's very understandable.
The teeth will weaken the area a little but the bottom of the overflow will add a good bit of rigidity to compensate for that so no worries there. 3/4" material would be fine for this, of course there are other factors like tolerances for bracing & deflection that might demand thicker material.

HTH,
James

 

[AMD30]

cool thx! so what other factors do you mean? i would need 1 in brace on top?

what about large openings on the top of tank like Blfuller is doing on his home made large tank? he has stated that he is using 3/4in material i believe.

 

[Acrylics]

Width of perimeter flange and crossbracing do affect the material thickness required, or the other way of looking at it - thicker material gives you more options as to how to brace it.

Blfuller's tank is a good example, if he had used 1" material, he could have had just 1 or 2 crossbraces and the same perimeter flange, or the same number of crossbraces (3) with much narrower perimeter flange, and maintained the same or actually less deflection.

With your 120 x 48 x 30" tank, you could get away with just one (8-10") crossbrace if you allowed for 6+" perimeter flange, assuming you stayed with 1" material. Or you could do a 5" flange and (2) 8" crossbraces, or 4" flange with (3) 7-8" crossbraces, all with similar deflection rates. I would not go with less than 4" eurobrace on that tank, esp on the short end which will have no crossbracing (I'm assuming here).
So thicker material allows for more options with this kind of thing.

HTH,
James

 

[dca22anderson]

Here is a picture of my external overflow box

Here is a picture of my external overflow box

I went with the external overflow on my 10' tank for the same reason...to save real estate.

looks like they used 1/2 inch on my external overflow box.

 

[AMD30]

what kind of bracing do you have on urs dca?

 

[dca22anderson]

the tank is fully braced on the top with 3-25" x 28" openings and 3/4" material on the top...

 

[dca22anderson]

This is a close up of the overflow.

Who did you end up going with to build your tank?

 

[AMD30]

i still havent decided.

are those dark pieces of plumbing your return lines? above the tank? you dont run the return thru the overflow box?

 

[dca22anderson]

I have the two returns in the overflow box on the closed loop oceans motions.

Yes, the 1-1/2" ABS feeds four 1" Sea Swirls on the top of the tank for the returns from the sump and filter room.

This allows me to push water from the long end of the tank towards the overflow in a circular motion...up from the closed loop to the returns shooting across the top of the tank toward the overflow.

 

[triggerfish1976]

I recommend Extrenal overflows especially if you are going with waveboxes.
I had my tank (600g 96x48x30) built specifically to accomodate waveboxes since internal overflows are not as efficient.
My overflow was installed to run along the back long axis of the tank to maximize surface skimming and to assure that I always had a constant flow over water leaving the tank. Some internal boxes have problems running dry when the water line dips below the top of the overflow.
Here are pics of my overflow.

 

[AMD30]

what are the dimensions of your over flow box? looks like you have 4x 1in drains?

what is the distance of the surface water to your top of the tank?

any suggestions for me to run 2 waveboxes?

any thing you would do different? noise?

how long are your teeth? i want an external overflow like that!

 

[triggerfish1976]

The box is 8"h x 6"d x 6'l. The drains are 1 1/2".
4" from the water surface to the top of the tank to accomodate the 2"-3" wave that I get.
I experimented with many different setups with my boxes. If you want the biggest wave possible I would run them side by side and upgrade the transformers from the 6100's to the 6200's. It will costs you a little money but it will give you close to an additional 1" wave. At one point I ran three waveboxes all side by side with the larger transformers and the wave was very strong in the tank to the point that some of my hovering fish like the Cardinals and gobies had a hard time staying in one place.

The cool thing about this setup is you get a real wave noise from the overflow due to the way the water drains into it from the motion created by the boxes. Some think that it is annoying but I like it. It sounds just like waves rolling onto a beach. You can also make it silent by installing taller Durso pipes in order to raise the flow in overflow.

Instead of using teeth I use gutter guard and roll it up and slide it into the horizontal slots that have been cut out along the back of the tank. The gutter guard works great because I can replace it anytime it starts getting gummed up.

One thing to consider is the thickness of the acrylic. I went with 1" to be on the safe side because the boxes do add a little more stress on a tank than other powerheads and wavemaking devices.