Overflow Help

[Lowredranger]

I am trying to get my design right on my tank am i am a little lost on the overflows. It will be a peninsular tank and i am trying to decide between 1 overflow box on the one end with 2 x 1.5" drains in it or 2 over flow boxes on the one end each with 1 x 1" and 1 x 1.5" both being used for drains. I will be running a dart as the return and i know 2 x 1.5" drains are rated for 3000gph, should i be worried if i only have the 2 drains?

Here is a sketch if i go with the two overflows instead of just one. I need some opinions on which way i should have it made, it will either be a glasscages or marineland tank. 72x36x25-27 Starphire on 3 sides. I will be using to start off the dart return run overhead to the other end of the tank and 3 vortechs.

Thanks
Jason

 

[Untamed12]

First...is there no way you can get put these overflow box(es) on the outside of the tank?

Also...is there a reason why you want the overflow box to be the full height of the tank? They probably only need to maybe 8" deep. Even if you are inside the tank, the bh's could still go through the back wall instead of the tank bottom.

Next...I assume you are doing a Herbie overflow. If not, start reading, because that is how you want to go. Doing a Herbie style with a single box will be slightly easier and require less hardware (lower cost)...but it requires some planning and having excess drain capacity.

I flow a Dart through 2 1.5" drains. The drains are restricted (Herbie), but I'm not sure you would want to be draining through 2 1" drains...

Finally...in your diagram it looks like you are tempted to go with multiple boxes because you have some other inputs coming in through the gaps. It would be creative, but you could run those right THROUGH the overflow box..or simply over them.

You want to maximize the LENGTH of surface intake in to overflow boxes to get the best surface skimming. That supports one overflow box that runs the entire width of the end of the tank.

 

[Lowredranger]

I am pretty sure i understand everything you stated above so here goes on the explanation.

I will read up on the herbie overflow but what i thought i was doing with the 2 boxes vs just one was having the 1.5" drain in each box valved which i thought was the herbie method but not sure and the 1" as the overflow in case the 1.5" gets too restricted, this being for quieter operation.

I was thinking if i went with one box in the middle with 2 x 1.5" drains valved and a single 1" as the backup/overflow.

I am unable to do the external overflow box with these two tank manufacturers as they do not offer it and my price range will not let me go to the other manufacturers.

I was attempting to place my 3 vortechs on that one side to keep the viewing free on the other sides. I figured i may need to add a 4th vortech after the initial setup. I will have my return come over the side of the tank and run to the opposite end to provide flow back towards the overflow.

If i make the overflow box to large or the entire width of the tank i will not have anywhere for the powerheads to go.

I assume i could make an internal overflow box the entire width that only went a depth of 6" or so with 3-4 drains out the side of the tank. I am saying i would need the extra drains b/c i was told that without the pressure of being deeper in the water the drains capacity would be limited.

Please advise further as i have been trying to learn as much as possible but it seems i still cannot get everything answered.

Thanks again for all of your help
Jason

 

[Lowredranger]

Ignore the holes that are in the bottom of the overflow box as i am not sure at this time of the size they need to be or how many. But here it is laid out for the single middle box.

 

[Lowredranger]

Here is the other design i think you were talking about, i figured
3 x 1.5" drains possibly. I am really not sure at this point, with this setup i would just be worried that my vortechs are too far underwater. As you can see i need some help.

Thanks
Jason

 

[Lowredranger]

Anyone have any more insights to my question? I would like to get this thing ordered today or tomorrow and i am still at an impass.
Thanks

 

[Untamed12]

<a href=showthread.php?s=&postid=13862294#post13862294 target=_blank>Originally posted</a> by Lowredranger
I am pretty sure i understand everything you stated above so here goes on the explanation.

I will read up on the herbie overflow but what i thought i was doing with the 2 boxes vs just one was having the 1.5" drain in each box valved which i thought was the herbie method but not sure and the 1" as the overflow in case the 1.5" gets too restricted, this being for quieter operation.

I assume i could make an internal overflow box the entire width that only went a depth of 6" or so with 3-4 drains out the side of the tank. I am saying i would need the extra drains b/c i was told that without the pressure of being deeper in the water the drains capacity would be limited.


Jason

You've got both points above exactly correct. Using smaller 1" drains as emergency drains could work, but it is slightly risky. Realistically, if the primary Herbie drains were to have a problem, they would probably still be flowing SOME water. But you might not be protected in the event of a 100% blockage in the Herbie drain. In that event, flow that used to be going down 1.5" drain has to find a way to go down a 1" drain instead. Might be enough...but it might not.

Safer to use another 1.5" as your emergency drains in both cases.

I just checked and my overflow boxes have about 5" of water head above the primary drains. That is using a Dart return through 2 valved 1.5" drains.

 

[Lowredranger]

So I assume you have a total of 4 x 1.5" drains with 2 of them as your emergency drains? Would i be safe going with 3 x 1.5" with one being the backup. If that sounds good i will just go with 1 slightly large overflow box with all 3 overflows in the same box.

Thanks again for all of your help.
Jason

 

["Umm fish?"]

Honestly, I've had sponges grow in and plug my overflows before. Plan on the flow being restricted at some point down the line and give yourself emergency backup capacity now, while it's still easy. You don't want your overflows to run anywhere near capacity.

On mine, I'm planning on two 2" overflows to handle the flow from 2 1" returns. I also have two extra overflows that will be higher than the other two and will be dry so no organics ever grow inside of them. That'll give me plenty of time to fix any problems that might occur with the bottom two overflows. (I want no repeats of the late night house floods.)

Good luck!

 

[Lowredranger]

Ok so now i am thinking my safety should be like 2" so even if they are both partially restricted it should be able to handle the extra or i could go with 3 x 2". I want this to be right but at the same time take up the least amount of room.

Thanks guys this has really got me thinking.
Jason

 

[Lowredranger]

Ok here is the final design. It will have a 14" wide overflow box with
2 x 1.5" drains and a 2" safety drain. I have a rep for marineland getting me a quote at the moment and we will see which one i will go with.

Thanks for help no i need to start updating the build thread.
Jason

 

[Untamed12]

The single 2" emergency is MUCH better than two 1" emergencies. You will probably be fine there.

Once you get setup, you'll want to do an exciting test....Shut off the valves on both the primary drains and verify that the 2" emergency can take all the flow. If it does, you'll be able to sleep very soundly.

 

[Untamed12]

<a href=showthread.php?s=&postid=13866237#post13866237 target=_blank>Originally posted</a> by Lowredranger
So I assume you have a total of 4 x 1.5" drains with 2 of them as your emergency drains?
Jason

Yes, that is exactly what I have.

 

["Umm fish?"]

2 x 1.5" drains and a 2" safety drain.

Yes, very good plan!

 

[Lowredranger]

Thanks guys if i can get the order out tomorrow i should have the tank on the 20th for glasscages.If i wait and go marineland i will just have 4 x 1.5" drains not sure on delivery.

Thanks again guys this was one thing i did not want to screw up.