Linear overflow size

[bookedirl]

Using the following input parameters

Gallons per Hour = 1325
Drain and Overflow sizes are calculated as

Recommended minimum drain pipe diameter = 1.5 inches
Recommended minimum linear overflow size = 20 inches


So, 1.5" PVC would be able to put out 1300 GPH assuming there was a pump to back it up. Where it says 20 inches.. the minimum linear overflow size... what exactly does it mean? I read in another post it says ALL THE SIDES added together.. what constitutes as all the size? Intake Pipe + Pipe to U Bend over the tank + Down Spout to Other U Bend to the T? Now Say I use the minimum or something a little higher.. will it be any less effective than one that uses say 5 or 6 feet of pipe?

Basically my reason for the question is I recently made an overflow out of 1.5" pipe for a tank that's about 18 inches high.. and I'll probably be moving it to a tank thats about 24 inches high.. so I want to make sure that it will work to it's full potential.

Thanks

 

[outlaw]

Using the following input parameters

Gallons per Hour = 1325
Drain and Overflow sizes are calculated as

Recommended minimum drain pipe diameter = 1.5 inches
Recommended minimum linear overflow size = 20 inches


So, 1.5" PVC would be able to put out 1300 GPH assuming there was a pump to back it up. Where it says 20 inches.. the minimum linear overflow size... what exactly does it mean? I read in another post it says ALL THE SIDES added together.. what constitutes as all the size? Intake Pipe + Pipe to U Bend over the tank + Down Spout to Other U Bend to the T? Now Say I use the minimum or something a little higher.. will it be any less effective than one that uses say 5 or 6 feet of pipe?

Basically my reason for the question is I recently made an overflow out of 1.5" pipe for a tank that's about 18 inches high.. and I'll probably be moving it to a tank thats about 24 inches high.. so I want to make sure that it will work to it's full potential.

Thanks

Linear overflow refers to the size of the overflow box not the actual pipe.

 

[hangner]

yep, the three side of the overflow box must at least add up to 20 inches to achieve 1325gph and your drain pipe (inside the overflow box) would have to be at least 1.5 inche but i would go for 2 pipes to be safe if one clogs
also you can always make ur existing pipe longer by adding an union..,

 

[bookedirl]

Ok, so you call the overflow a box.. even though it's not a box? Or am I confusing a box with the overflows you can buy already made? Still not sure about one of the other questions I asked... Wear the overflow I made doesn't reach the bottom of the new tank which is about 8inches taller.. will that make a difference in the performance of the overflow?

Thanks

 

[outlaw]

Technically it is a box, I just has no top, hence it overflows into the box. Look at this picture( PICTURE #2) and imagine if it were to suit your application. The long side in the front of the picture is lets say 12 inches wide. That means That the two short sides that touch the wall of the aquarium would be 4 inches wide per side. Therfore you have your 20" of linear overflow.

If the box does not go all the way to the bottom then yes it will affect the performance of the overflow so you would need to increase either the size or number of your pipes leading to the sump. But IMHO if you are drilling the side its kind of pointless to even have the overflow box, I would say to scratch it all together.

http://glasscages.com/?sAction=Overflows

 

[bookedirl]

I'm talking about a DIY overflow, not one that's already pre-drilled in the tank. I described it in my first post... with the 3 U Bends... So it's a little different.. no?

 

[bookedirl]

Can anyone give me a hand with this? I'm still up in the dust as I think the two that responded were under the impression I was talking about a drilled tank. If they weren't then I'm still lost.

 

[Danh]

Yes, they were thinking of overflow boxes that are drilled. I believe that 1x1.5" may work for 1300gph. I used a mag 9.5 at 4' of head with two 3/4" DIY pvc overflows on a 75g tank. They had no problem. The lenth height of the pieces also affects it's flow, the longer the pieces, the more flow. So with a tank taller than a 75g, that you could fit a taller overflow on, you could get more. Try the 1.5" and if it's not enough, make another one to go with it.

 

[outlaw]

Sorry I was under the impression that you were talking about a drilled tank. The height of the pipe does have a lot to do with the performance. But if you make one for the smaller tank and it will handle the flow, then it will work on the bigger tank also.once again sorry for the confusion.

 

[CHOMPERS]

Using the following input parameters

Gallons per Hour = 1325
Drain and Overflow sizes are calculated as

Recommended minimum drain pipe diameter = 1.5 inches
Recommended minimum linear overflow size = 20 inches


So, 1.5" PVC would be able to put out 1300 GPH assuming there was a pump to back it up. Where it says 20 inches.. the minimum linear overflow size... what exactly does it mean? I read in another post it says ALL THE SIDES added together.. what constitutes as all the size? Intake Pipe + Pipe to U Bend over the tank + Down Spout to Other U Bend to the T? Now Say I use the minimum or something a little higher.. will it be any less effective than one that uses say 5 or 6 feet of pipe?

Basically my reason for the question is I recently made an overflow out of 1.5" pipe for a tank that's about 18 inches high.. and I'll probably be moving it to a tank thats about 24 inches high.. so I want to make sure that it will work to it's full potential.

Thanks

Where did you get this information? It sounds like the first person knew what they were talking about followed by people who thought they knew what they were talking about. The blind leading the blind, if you will...

Moving the overflow from the 18" tank to the 24" tank will not affect the performance. The only way to improve the performance is to build one for the 24" tank. The overflow is syphon powered, so to increase the power, you need to build it so that the inside bottom loop reaches to the bottom of the tank.