calfo overflow

joshuaroot · 08/16/2006, 06:48 PM

ok i got my tank today its a 120 48"x24"x24" and i am gonna put this style overflow in it i am going 38" long by 4" out from the back of the tank and 5" deep. there will be 3 1" bulkheads drilled into the overflow in the back of the tank. is this a good idea? bad idea? what should i do to make it better? its a brand new tank so i can do anything!

sjm817 · 08/16/2006, 07:22 PM

Good choice on the overflow design. I would make it more like 38x2.5x4 so it doesn't use up so much tank space.

joshuaroot · 08/16/2006, 07:24 PM

i wanna be able to put 90 degree elbows on the bulkheads tho if its loud.

sjm817 · 08/16/2006, 07:40 PM

Instead of a 90, you can use a piece of PVC cut in 1/2 or at an angle. If you are looking at the PVC on end, cut it so it is a "C" instead of an "O". The open side goes down. You just need to close off the top. Elbows take up a lot of space.

joshuaroot · 08/16/2006, 07:55 PM

what if i came out of the bulkhead with a tee and went up to a cap with a hole instead?

sjm817 · 08/16/2006, 08:04 PM

I guess that would work. I think the PVC cut in 1/2 would be fine, simple and would save space. One of the ideas of the Calfo is to use up less space in the tank compared to a traditional overflow. I would want it sticking out into the tank as little as possible.

joshuaroot · 08/16/2006, 08:08 PM

i am not following you on what u mean by cutting it in half

sjm817 · 08/16/2006, 08:14 PM

Let me see if I can do this without drawing a pic...

Picture your bulkhead with a piece of PVC sticking out of it long enough so it touches the other end of the overflow. If you looked at the end of the PVC, its a circle. You want to cut the PVC in 1/2 lengthwise so you would have a 1/2 circle. The open end of pipe would be facing down.

joshuaroot · 08/16/2006, 08:26 PM

ok thats what i was thinking you were talking about.

joshuaroot · 08/16/2006, 08:40 PM

so would 1/4" glass be thick enought for doing this? and would three 1" bulkheads be good to?

vortex6 · 08/16/2006, 09:55 PM

I used 1/4" glass for mine and it's working great. You don't need too thick of glass since you won't have much water pressure on a calfo design. You'll only have around 25 gallons of water pressing against a 5" deep box. I also put in 4 1" bulkheads on my 180 gallon so you should be good with 3.

joshuaroot · 08/19/2006, 12:51 AM

ok have the overflow made 38"x2.75"x5" now how far from the top of the tank should i put the over flow in the tank?

sarduci · 08/19/2006, 07:46 AM

Slightly below the top? Where else would you put it? *confused*

Where ever you put its top edge is where your water level will be in your tank.....

joshuaroot · 08/19/2006, 10:51 AM

would be puttin it at the bottom of the black ring be a good place? or is that to low?

joshuaroot · 08/21/2006, 01:27 PM

will this work for my drain lines? i mean will it be quiet? and suggestions?

seanb · 08/21/2006, 01:38 PM

I would put the overflow a little higher. Somewhere between the top and half-way down the black trim. I put mine 1/4" below the top. That way you don't see the waterline when looking at the tank.

sjm817 · 08/21/2006, 01:47 PM

I would put it just at the bottom of the black trim. The water level will be slightly above that when running.

joshuaroot · 08/21/2006, 01:49 PM

what about the drains on the back of the tank? will that work fine?

sjm817 · 08/21/2006, 01:57 PM

Looks ok to me.

DaveBrader · 08/29/2006, 09:48 AM

I have a question for those of you experienced with this style overflow. Why can't it be the entire length of the tank, and only one inch in from the back and say 4 inches deep or just enough to cover the bulkhead holes?

Dave

DaveBrader · 08/29/2006, 09:53 AM

With two 2" inch drains, and 36 inches of linear flow, you can get 2400 GPH. Why the need for a 4 inch intrusion into the tank? It would seem to me, that if you have a 60 inch tank, then a 60 inch linear flow, 1 inch from the back, 4 inches deep with three one inch bulkheads would be killer and take all the flow you could ever need. The one inch intrusion into the tank would be nearly impossible for all but the very smallest of livestock to get into.

Cover each bulkhead with some of this stuff, and I think the overflow would be very secure from anything getting into it.

http://www.garden-zone.com/cloth.html

Am I missing something?

Dave

seanb · 08/29/2006, 10:36 PM

There is nothing wrong with making the overflow the entire length of the tank and as you pointed out it greatly increases you're linear flow. It is my understanding that the original "Calfo overflow" was full length.
People have chosen to shorten their overflows for various reasons, some don't want to sacrifice that much visible area, some want more space for other plumbing to come over the back, in my case I have an older tank with a wide center glass brace and I didn't want it covering the overflow ( in case I needed to reach in to clean or rescue something).
As for the width, you can go narrower, 4 inches seems to be popular and I think it is because some people add street elbows to the bulkhead on the inside to reduce noise and it also gives you room to get your hand in there if necessary.

DaveBrader · 08/30/2006, 12:39 AM

Ok, so the real reason for making the overflow say 4" wide back to front of tank is just to have room to get into the overflow if you need to for some reason. I can not really think of a reason you would need to, especially if it was only 1 inch wide. At that width, not much could get into it except water. Thanks,

Dave

Kshack · 08/30/2006, 08:40 AM

Try to put a bulkhead into anything less htan 3 inches. You need room to slide the threadeed end in. If you put them in backwords, taking up less room, they will leak.

DaveBrader · 08/30/2006, 08:45 AM

I can put the bulkhead in before the overflow can't I ?

Dave

08/16/2006, 06:48 PM	#1
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	calfo overflow ok i got my tank today its a 120 48"x24"x24" and i am gonna put this style overflow in it i am going 38" long by 4" out from the back of the tank and 5" deep. there will be 3 1" bulkheads drilled into the overflow in the back of the tank. is this a good idea? bad idea? what should i do to make it better? its a brand new tank so i can do anything!

08/16/2006, 07:22 PM	#2
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Good choice on the overflow design. I would make it more like 38x2.5x4 so it doesn't use up so much tank space. __________________ - Scott

08/16/2006, 07:40 PM	#4
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Instead of a 90, you can use a piece of PVC cut in 1/2 or at an angle. If you are looking at the PVC on end, cut it so it is a "C" instead of an "O". The open side goes down. You just need to close off the top. Elbows take up a lot of space. __________________ - Scott Last edited by sjm817; 08/16/2006 at 07:53 PM.

08/16/2006, 08:04 PM	#6
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	I guess that would work. I think the PVC cut in 1/2 would be fine, simple and would save space. One of the ideas of the Calfo is to use up less space in the tank compared to a traditional overflow. I would want it sticking out into the tank as little as possible. __________________ - Scott

08/16/2006, 08:14 PM	#8
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Let me see if I can do this without drawing a pic... Picture your bulkhead with a piece of PVC sticking out of it long enough so it touches the other end of the overflow. If you looked at the end of the PVC, its a circle. You want to cut the PVC in 1/2 lengthwise so you would have a 1/2 circle. The open end of pipe would be facing down. __________________ - Scott

08/16/2006, 07:24 PM	#3
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	i wanna be able to put 90 degree elbows on the bulkheads tho if its loud.

08/16/2006, 07:55 PM	#5
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	what if i came out of the bulkhead with a tee and went up to a cap with a hole instead?

08/16/2006, 08:08 PM	#7
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	i am not following you on what u mean by cutting it in half

08/16/2006, 08:26 PM	#9
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	ok thats what i was thinking you were talking about.

08/16/2006, 08:40 PM	#10
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	so would 1/4" glass be thick enought for doing this? and would three 1" bulkheads be good to?

08/16/2006, 09:55 PM	#11
vortex6 Registered Member Join Date: Jul 2006 Posts: 23	I used 1/4" glass for mine and it's working great. You don't need too thick of glass since you won't have much water pressure on a calfo design. You'll only have around 25 gallons of water pressing against a 5" deep box. I also put in 4 1" bulkheads on my 180 gallon so you should be good with 3.

08/19/2006, 12:51 AM	#12
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	ok have the overflow made 38"x2.75"x5" now how far from the top of the tank should i put the over flow in the tank?

08/19/2006, 07:46 AM	#13
sarduci Premium Member Join Date: Jul 2004 Location: Wausau, Wisconsin Posts: 1,278	Slightly below the top? Where else would you put it? confused Where ever you put its top edge is where your water level will be in your tank.....

08/19/2006, 10:51 AM	#14
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	would be puttin it at the bottom of the black ring be a good place? or is that to low?

08/21/2006, 01:27 PM	#15
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	will this work for my drain lines? i mean will it be quiet? and suggestions?

08/21/2006, 01:38 PM	#16
seanb Premium Member Join Date: May 2003 Location: Central Coast, CA Posts: 236	I would put the overflow a little higher. Somewhere between the top and half-way down the black trim. I put mine 1/4" below the top. That way you don't see the waterline when looking at the tank. __________________ The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny..."' - Isaac Asimov Current Tank Info: 225 gal reef tank

08/21/2006, 01:47 PM	#17
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	I would put it just at the bottom of the black trim. The water level will be slightly above that when running. __________________ - Scott

08/21/2006, 01:49 PM	#18
joshuaroot Registered Member Join Date: Mar 2004 Location: Cuyahoga Falls, Ohio Posts: 266	what about the drains on the back of the tank? will that work fine?

08/21/2006, 01:57 PM	#19
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Looks ok to me. __________________ - Scott

08/29/2006, 09:48 AM	#20
DaveBrader Registered Member Join Date: Jun 2004 Location: St. George Utah Posts: 268	I have a question for those of you experienced with this style overflow. Why can't it be the entire length of the tank, and only one inch in from the back and say 4 inches deep or just enough to cover the bulkhead holes? Dave

08/29/2006, 09:53 AM	#21
DaveBrader Registered Member Join Date: Jun 2004 Location: St. George Utah Posts: 268	With two 2" inch drains, and 36 inches of linear flow, you can get 2400 GPH. Why the need for a 4 inch intrusion into the tank? It would seem to me, that if you have a 60 inch tank, then a 60 inch linear flow, 1 inch from the back, 4 inches deep with three one inch bulkheads would be killer and take all the flow you could ever need. The one inch intrusion into the tank would be nearly impossible for all but the very smallest of livestock to get into. Cover each bulkhead with some of this stuff, and I think the overflow would be very secure from anything getting into it. http://www.garden-zone.com/cloth.html Am I missing something? Dave

08/29/2006, 10:36 PM	#22
seanb Premium Member Join Date: May 2003 Location: Central Coast, CA Posts: 236	There is nothing wrong with making the overflow the entire length of the tank and as you pointed out it greatly increases you're linear flow. It is my understanding that the original "Calfo overflow" was full length. People have chosen to shorten their overflows for various reasons, some don't want to sacrifice that much visible area, some want more space for other plumbing to come over the back, in my case I have an older tank with a wide center glass brace and I didn't want it covering the overflow ( in case I needed to reach in to clean or rescue something). As for the width, you can go narrower, 4 inches seems to be popular and I think it is because some people add street elbows to the bulkhead on the inside to reduce noise and it also gives you room to get your hand in there if necessary. __________________ The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" but "That's funny..."' - Isaac Asimov Current Tank Info: 225 gal reef tank

08/30/2006, 12:39 AM	#23
DaveBrader Registered Member Join Date: Jun 2004 Location: St. George Utah Posts: 268	Ok, so the real reason for making the overflow say 4" wide back to front of tank is just to have room to get into the overflow if you need to for some reason. I can not really think of a reason you would need to, especially if it was only 1 inch wide. At that width, not much could get into it except water. Thanks, Dave

08/30/2006, 08:40 AM	#24
Kshack Registered Member Join Date: Jan 2006 Location: Ridgefield, WA Posts: 202	Try to put a bulkhead into anything less htan 3 inches. You need room to slide the threadeed end in. If you put them in backwords, taking up less room, they will leak.

08/30/2006, 08:45 AM	#25
DaveBrader Registered Member Join Date: Jun 2004 Location: St. George Utah Posts: 268	I can put the bulkhead in before the overflow can't I ? Dave