Weir question

C

CoolWaters

Superstar Fish
#1
Dec 10, 2006
1,028
1
0
Milpitas
#1
im trying to bring water over the wall of my fish tank.

heres the site the explains it if you dont know what it is.

DIY Overflow Box


for people that do know.

im having trouble calculating the amount of water it siphons...

the intake (U tube) is 3/4" wide and 3" long. so 3/4" tube basically.

theres a one inch fall. is it enough to siphon 120gph?

probably not...how long should i make it so it can at least siphon 120g?

and im trying to keep it at 3/4" wide. i had some problems before with wider ones...

or should i increase the fall distance?
 

Pure

Pure

Elite Fish
#2
Nov 1, 2005
3,216
7
0
Jacksonville, FL
#2
What kind of problems did you have?

It shouldn't matter much unless 120 gph is emtying your sump out. On my sump for my 125 all I have is a 1 inch U tube in the over flow box and it has no problems keeping up with the 600 gph pump in the sump.

I'm pretty sure (corect me if I'm wrong) that with a sump the over flow box will only pull what is put in the tank by the pump. When it's set up properly that is.
 

C

CoolWaters

Superstar Fish
#3
Dec 10, 2006
1,028
1
0
Milpitas
#3
wow 600 gph with a 1" tube... thats the fall rate?

iv noticed 1/2" and suck out quite a bit with a fall rate of 2.5 feet....flooded my living room...

by pump do u mean siphon? my pump returns 120 gph but not sure if its the whole 120 gph since i has to move through 3 elbows and 1 feet of 1/2" tubing.
 

Joe Fish

Joe Fish

Superstar Fish
#4
Apr 21, 2006
2,126
1
0
Penn State
josy.isa-geek.com
#4
Elbows are bad for the return line. Make it as straight as possilbe or use a 'U' joint if you can't get around it. I think you want the return pump to push more GPH than your overflow then just put a ball valve on it to turn it down.
 

Joe Fish

Joe Fish

Superstar Fish
#8
Apr 21, 2006
2,126
1
0
Penn State
josy.isa-geek.com
#8
I know what you mean. I can't drill my tank because I am not going to empty it. I'm still working out the plans so I can have my return line be as straight as possible.

You could always get a bigger return pump and put a ball valve on it.
 

C

CoolWaters

Superstar Fish
#9
Dec 10, 2006
1,028
1
0
Milpitas
#9
i heard putting a ball valve puts a strain on the pump.

i dont mind losing a couple of gph. my friend acually recommended me doing a contained drill so that pieces of glass dont get in the water. of course u have to drain it a little thou.

im going to stick with that 3" by 1/4" tube. i hope thats enough or i'll be forced to use my 80 gph pump...
 

Joe Fish

Joe Fish

Superstar Fish
#10
Apr 21, 2006
2,126
1
0
Penn State
josy.isa-geek.com
#10
You can put a ball valve on and then also plumb a 'U' piece that goes back into the sump. This way you would have 2 ball valves and the would be less strain. If you read the sump section on melevsreef.com you'll understand what I'm trying to say.
 

Dadstank

Dadstank

Large Fish
#12
Nov 4, 2006
162
2
0
Minnesota
#12
A 1" bulkhead or hole will flow approximately 600 GPH if that helps any.

If you are still having probs I can put up some pictures of my weir overflow... or you can look in the "rate my tank" section.

I bought my overflow online for about $42 with shipping. Making one can be a PITA if you don't have the right tools.... I worked in plastics for 8 years.. I know firsthand...

From my experience, a ball valve only puts some back pressure on the pump but doesn't hurt it.

I'm flowing about 450GPH thru my weir overflow and I know it can handle more easily.
 

J

JeLeAk

Large Fish
#13
Jan 4, 2005
491
0
0
40
Alaska
#13
Joe Fish said:
Elbows are bad for the return line. Make it as straight as possilbe or use a 'U' joint if you can't get around it. I think you want the return pump to push more GPH than your overflow then just put a ball valve on it to turn it down.
Click to expand...
i have 3 90's in my return line the piping is also 1" and i dont have a problem

on mine my return pump is slightly less than what my siphon/overflow box is rated at... i think a valve on the pump will put more stress on the motor and cause premature wear and damage... it also made for setting up a lot easier seeing how no matter how much water the return moves the overflow will handle it, unlike with a return pump that you gota "calibrate"
 

C

CoolWaters

Superstar Fish
#14
Dec 10, 2006
1,028
1
0
Milpitas
#14
yeah since my weir is going to be hand made i dont really know the rate of flow.
all i need is the glue. im going to a plastic store then cut everything for me. 17 pieces. very small too, so i wonder if they'll get annoyed.
 

T

TheFool

Large Fish
#16
Apr 19, 2006
323
2
0
#16
I wouldn't worry if you're going to continue to return thro' a section of 1/2 tubing as that is really going to kill your flow rate. I think you need to remove that, it's a bigger problem than the elbows.
 

C

CoolWaters

Superstar Fish
#17
Dec 10, 2006
1,028
1
0
Milpitas
#17
TheFool said:
I wouldn't worry if you're going to continue to return thro' a section of 1/2 tubing as that is really going to kill your flow rate. I think you need to remove that, it's a bigger problem than the elbows.
Click to expand...
the power head has out put of 1/2" so im pretty stuck there.

i might even have to change the HOB refuge into a intank refuge so its cheaper and less complicated....on the plus side theres going to be a platform for light hungry coral later.
 

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