Calfo Style Overflow boxes

[douggiestyle]

im not sure i understand you hampton. could you elaborate.

also im still not sure of those elbows. it would seem to me that you would get a siphon that would suck and glop and make all sorts of noise. unless im missing something.

 

[Hampton]

Doug,

The original post is in this thread somewhere for both the elbows and the U-shaped plastic. In the one case, with the elbows, I think you get a syphon which causes any sucking and glopping sound to be muffled by the elbow and water. The sucking and glopping sounds are probably hidden by traveling through those media instead of being open to the air to be heard by all.

The upside down U probably just serves as an elbow without taking up all of the space. The U cups over the entrance to the bulkhead and hides the glopping sounds on top, while the water serves to hide the sounds on the sides and the bottom.

I don't see why people don't just cut the elbow down to a short 90 degree coupling. They are designed to withstand many pounds of internal water pressure. They have at least 1/2" of overlap at each joint. Many have 1". You can saw the end of the PVC piece off close to the actual elbow.

I've even sawed off the entire arm from one and used a dremel tool to ream out enough plastic up inside the elbow to allow a joint to be made with 1" less extension beyond the end of the straight pipe to which I was connecting the elbow. If all it's there for is to block gurgling noises, it doesn't have to withstand even 1/2 psi.

 

[Hampton]

Also, if you're thinking the U would create a whirlpool down to the opening and that would make noise, I just don't think we're talking about that much water flow.

 

[Hampton]

To elaborate on my slot idea, picture the back wall of the overflow box with a hole cut in it. The hole is used to allow the bulkhead to go through the box while securing the box to the back wall. Instead of cutting a hole in the back wall of the overflow box and assembling the bulkhead through it, Cut a slot in the back wall of the box and slip it onto the bulkhead from the bottom.

Then, use a chunk of the remaining material from the box to back fill the area of the slot that you cut out. That way, when the bulkhead gaskets are secured to the walls, they will seal the back wall of the tank to the bulkhead. Without that missing slot material, there would be a gap that would not apply pressure to about 1/4 of the diameter of the gaskets, and leaks would surely develop.

 

[Hampton]

<a href=showthread.php?s=&postid=8316065#post8316065 target=_blank>Originally posted</a> by Hampton
Also, if you're thinking the U would create a whirlpool down to the opening and that would make noise, I just don't think we're talking about that much water flow.

It's not actually a syphon. It's really water pushing into a hole because of excess water on the one side. With an elbow turned down, the water enters the bottom of the elbow, travels up and around the bend due to excess pressure on the tank side, and then falls into a bottomless pit. As it goes over the edge, it will chug and gurgle as water and air mix and slosh.

With the elbow, those sounds are blocked by the plastic around the sides and the water at the tank end. On the other end, it is blocked by plastic tubing all the way down to wherever it opens up, generally under water in your sump.

Without the elbow, on the tank side, the water/air sloshing is open to be heard by all.

Analogy: With the elbow, it's like opening a hole in the middle of the back of the tank well below the water line. Water rushes out and doesn't make any noise until you see it and scream, or until it hits the floor.

Without the elbow, it's like most people's overflow pipes which gurgle and slosh and make noise without ever hitting the floor.

 

[Hampton]

I came up with a solution to no teeth - Have a horizontal overflow the length of the back wall (coast to coast), and have a second glass piece above it about 1/4" the entire back length of the wall - I'll dub that a horizontal tooth.

Here's my plan: 90 gallon rimless tank with the back wall 1" lower than the other three. 1/4" above the back wall, one horizontal tooth the length of the tank - it can have a couple of small supports.

Attached to the back of the tank by silicone is the overflow box. It is the entire width of the tank too. It has 4 holes in the bottom which T off into two which lead to the sump.

I'm referring to this as an External Calfo design, though it should be called a Hampton.

The key principles are:

Long Horizontal overflow for max skimming.
No vertical teeth which would impair skimming.
External box for minimum intrusion into the tank.
1 Horizontal tooth to keep most critters on Display side.

My horizontal tooth will probably be 2" wide, and angles forward. I want the top of it to be below the top of the sides and front (a second level overflow, just in case), and the 2" width gives it strength. It's tilted forward to keep the top below that of the other sides - genius?

The tank will have 5 holes drilled in the back for a closed loop flow system. I think the outflow will be a 1 1/2" bulkhead, and the others will be 1" bulkheads (2 on at a time for return flow). One 1.5 exceeds 2 1's in flow capability.

What do you think?

 

[douggiestyle]

ok i understand about the slots hampton (who do you fly for).

i dont think that would be an option. as you stated it could leak and im sure it would unless one sealed the "fill" with silly con. that makes me a bit nervous.

as far as the elbows i still dont understand how, once they started flowing, a siphon would be adverted.

 

[BeanAnimal]

Sounds like a lot of work for no gain. I have a 4' internal overflow and don't have critter problems. The only things that go into the overflow area are snails. If you that concerned put a partial lid on the overflow box, maybe a 1/4" back from the front edge. All of this angled tooth stuff is just too complicated for the task at hand.


A lot less complicated. As far as the overflow box.. internal or external. that is your choice. Lowering the back glass 1/2" or so is nothing new (it is the basic waterfall overflow design used in some aqariums, swimming pools, etc... and is an option if you are custom building a tank. The pre-fab tank folks have to cut a slot (risky) or holes to allow the water into the external overflow area. My next tank will certainly have external overflow box instead of the internal shelf... no "tooth" though.

Check out the large tank forum... a guy built a HUGE plywood tank with a shallow external overflow box on the back. (his kid was sitting in the overflow) if that gives you any idea. The folks there will know the thread... just ask.

 

[Hampton]

Thanks, BeanAnimal.

The horizontal tooth is no hassle at all. One piece of glass 2" by 48" glued in just above the back wall with the top leaning forward so that the top of it is below the level of the sides and front. This will form the "Slot" of which you speak.

 

[Hampton]

Doug,

In order for a syphon to start, the tank side has to be below water level (it would be) and the drain side would have to be sealed to a point below the level of the water in the tank (it would not be). I am by no means the expert on these noise reducers, except that I read this entire thread 2 nights ago. For the complete rig, they put a T on the outflow side. On the end that points up, I believe they cap they end and drill a hole in it. This blocks almost all of the noise and the hole prevents a syphon.

John

I am on Mil Leave from Delta and Fly F-15's in the Fl ANG. How about you?

 

[agarza]

check this site, www.dursostandpipes.com there you'll find everything you want to know about the noise reducers.

 

[douggiestyle]

ok i didnt know they were using dursos with these things. i was only going by the pics i saw.

hampton, f-15 sweet. my bud is at 911th afr, flys c130. major chuck sargent.

thought id ask. i know a lot of pilots. sometimes there are small circles. but, no i m not a pilot.

 

[douggiestyle]

ok i didnt know they were using dursos with these things. i was only going by the pics i saw.

hampton, f-15 sweet. my bud is at 911th afr, flys c130. major chuck sargent.

thought id ask. i know a lot of pilots. sometimes there are small circles. but, no i m not a pilot.

 

[dtaranath]

douggiestyle:

is your avatar some sort of copepod? pretty funny.

 

[jdircksen]

Good read.
I plan on doing a full length Calfo on my 75g. I'll use 2 or 3 1" bulkheads; not sure yet. Should I run one directly into a skimmer? Or should I just join them all into 1.5" and run them to the sump?

 

[Hampton]

I'd try running one into the skimmer. I plan on trying that when I transfer my new tank in.

 

[Jeremy Blaze]

<a href=showthread.php?s=&postid=8646583#post8646583 target=_blank>Originally posted</a> by jdircksen
Good read.
I plan on doing a full length Calfo on my 75g. I'll use 2 or 3 1" bulkheads; not sure yet. Should I run one directly into a skimmer? Or should I just join them all into 1.5" and run them to the sump?

Yes, it will work better.

 

[Hampton]

<a href=showthread.php?s=&postid=8646694#post8646694 target=_blank>Originally posted</a> by Hampton
I'd try running one into the skimmer. I plan on trying that when I transfer my new tank in.

OK, so I said that I would, but I had not. So, now I've put my plumbing where my mouth is (does that sound bad?) and I've plumbed it with one overflow drain pipe going directly to the intake on my EuroReef RS-100. I can't wait to see all the great new skimmate I'll be getting.

I did not seal any of the fittings inside the sump, so there is some leakage into the sump. The good news is that the overflow box overloads the intake of the skimmer, and the excess seeps into the sump. There are some bubbles coming down with the water, and those bubbles escape out of my weakest fitting into the sump.

When I install my new tank, I'm expecting to be able to control the flow more easily and avoid air coming down the pipe with the water. Right now, if I raise the water level in my overflow box to to the point that the skimmer intake draws only water and no air, the water level in my tank goes up so high that it reaches the extremely extensive euro-bracing, and messes up the surface flow. That is one of my main reasons for replacing the tank - too much glass on top, not enough open surface area for light and cooling.

 

[drstupid]

i'd encourage you all to look at sanjay joshi's personal tank design in the large tank forum. he calls it "500 gallon dream system" or something, i've been subscribed to it so long i can't remember.

i copied most of his tank design for my (itsy bitsy) 120, his design includes side bulkheads for feeding a skimmer directly from the overflow (presumably via a pump and not gravity though), and he has some good CAD schematics to help visualize how the whole system works.

from my own setup, my observations are:

- external is better, you need that distance from the wall for your rear plumbing anyways.

- put a slab of black acrylic across the back glass, it hides all your plumbing and looks much neater.

- the back glass only needs to be about 1/4" lower than the other three walls.

- twin dursos work great. you definitely want more than one drain line for redundancy.

- you want your dursos set to keep the overflow level about 1" below the lip, there's a balance between the noise of the water rushing over the edge and efficiently skimming the top surface of the tank.

- the overflow itself ends up being very nutrient rich (i.e. a good place to feed your skimmer),
so with splash from your lights you end up with a good amount of algae growth. which makes your snails at least welcome visitors, you don't want any sort of teeth or screening preventing them access. none of my other mobile guests have made their way into the overflow, although the durso's sip so gently i've considered using it as a refugium for new fish coming out of QT. i'm doing about 8-10x turnover from the sump, which is pretty high.

- the overflow makes a great place to hang specimen containers with new corals, especially things like unanchored zoas. water naturally flows into the container without causing a lot of turmoil, and you get a good indirect lighting. it's also a good place to float bags, especially if your sump is on another floor.

i'd be happy to post some pictures if they'd help, there were a few design challenges i had to overcome introduced by the overflow. i would recommend checking out sanjay's progress.

for a plug, my tank was built by chris knox in pottstown, pa, and i'd recommend him to anyone looking into a custom tank with this design. www.oceanimage.net

pete

 

[Hampton]

Is it " 500G (84X48X30)- In the works to become real "

If so, about what page or date should we search?