Another Calfo Overflow question

sscheitel

New member
I am planning a 265 gal reef tank

I plan on doing a c-c or calfo overflow accross the entire back of the tank.

I was going to do (3) 1" bulkheads tee'ed and vented (durso style) with the 90 degree elbow in the overflow.

What 90 degree elbow connects to the bulkhead inside the overflow? Is it a 1" street ell ?

Will three of these 1" drains be enough?

I am going to have (2) 3/4" returns driven by (2) MAG 9.5 pumps.

Flow is not the main goal here...1000-1200 gph will suffice. After all that is all my PM Bullet-3 with PanWorld 150 will drive.

I have a Tunze 6100 w/7095 to go in the tank for flow.

I have read all the threads...none address such a large tank
http://www.reefcentral.com/forums/showthread.php?s=&threadid=619976

Should I just got with 1.5" bulkheads? If so...how many ?

The reason I am thinking about (3) 1" bulkheads is because I can get the 90 degree elbow on the inlet making the actual overflow only 3" x6"...not too obtrusive

If I have to jump to the 1.5" street ell....I will have to make a considerably larger overflow in the aquarium.

Should I do (4) 1" bulkhead drains?....I do not know.

but I wanted to get more input....

Thank You
 

Randall_James

Premium Member
Well going by typical specs, you need 3X to 5X flow. On the high side you are looking around 1300Gph. I do not have the gravity flow rate of 1" but 1.5" can pull about 800Gph , I think I would go with two 1.5 inch just to keep things less complicated.

I have a modified Calfo setup that I am running flat vinyl hose on and it is amazingly quiet (the sound is similar to one of those little rock gardens people buy for the sound of the water running over them). I have had this up and running for about 6 months and have no plans on making any changes to it . The return is on the left side and the fitting on the right side is the intake for the closed loop.

normal_DSCN2115.JPG
 

BeanAnimal

Premium Member
I would go with more than (3) bulkhead (even if you do not use them) and would go with larger than 1".

I run (3) 1" on a 75 gallon tank with close to 1500 going through the sump. My sump is as large as the tank and hold LR. It may not be the most efficient setup...

If you do not plan to go over the sump flow you stated, then (3) 1" bulkheads will certainly do.

Here is how I would set it up:

(2) with down turned elbows
(1) with un upturned elbow and strainer

External standpipes capped with john guest valves threaded into the caps.

Ball valves just below the TEEs that form the external standpipes.

Standpipe #1 will be wide open with an open air valve also
Standpipe #2 will be partially closed with a fully closed air valve
Standpipe #3 will be fully open with a CLOSED air valve. This is the standpipe with the upturned elbow.

The Situate the upturned elbow and strainer such that it stays dry unless the water nears the top of the trim. This is your emergency overflow. The AIR valve is closed so that it (the standpipe) can pull a full siphon (flush like a toilet) in case the other standpipes cloge for some reason.

Standpipe #2 will be used to regulate the flow through standpipe #1. Becuase #2 has a closed air valve, it will pull a full siphon as well. Adjust this standpipe so that it DOES NOT handle the full flow of the return pump. This will force a small amount of excess water to flow down standpipe #1.

The system will be very stable and fairly self tuning. Because standpipe #2 is at full siphon, NO AIR will be pulled down to the sump. Because #2 takes most of the flow, water will cascade down #1 and pull very little air with it.

The net result is a DEAD SILENT overflow with NO AIR entrainment in the sump. The emergency overflow protects the floor.

Bean
 

GuySmilie

Premium Member
Re: Another Calfo Overflow question

<a href=showthread.php?s=&postid=9872125#post9872125 target=_blank>Originally posted</a> by sscheitel

I am planning a 265 gal reef tank......Should I do (4) 1" bulkhead drains?....I do not know.

but I wanted to get more input....
Thank You

Here's what I did to my 58g.

Like Bean said, why not go with 4?
Heck since you will have a full width overflow on such a big tank, why not put in six? Just plug the extras for spares. If you go with 1" bulkheads you will be able to fabricate your overflow box to have a little less depth, ie, closer to the wall. If you find out you need more flow, just tap into one of the spares.
 

BeanAnimal

Premium Member
Also with such a wide overflow, you could easily use a few of them for CL intakes and still keep a very thin layer of water going over the weir.
 

Randall_James

Premium Member
The idea behind the overflow is to capture only the very top layer of water off the tank and to keep this effluent as concentrated as possible. This effluent should match as close as possible to 100% of skimmer flow (Ideally 2 skimmers and they are cleaned on alternate days) Running this effluent to an area that feeds only the skimmer is also suggested. (these are the suggestions by A.Calfo)

Running this overflow for the closed loop will only serve to dilute the effluent and make the skimmers work harder to get the DOS out. (if you drop a note to Anthony, he will be more than happy to respond btw, probably worth the few minutes it takes)
 

sscheitel

New member
Thank You all for the input.

Bean,
If the power goes out...will #2 (full siphon) prime itself without me doing anything?

....also....as long as I am driving enough water to the sump and not returning more than the bulkheads can handle...why do I need the guest valves? and why the full siphon.

I currently have a 90 gal - 1" bulkhead w/durso stand pipe...no john guest valve...running a MAG 9.5...the bulkhead is more than capable of the flow that the 9.5 is returning. The result is a quiet overflow. As long as I stick to this principle...why do I need the full siphon on #2?

I love the idea of the upturned 90 degree elbow for emergency blockage. I will definetly be making a 4th drilled hole for this.

Well...hit me with your thoughts....

Thanks
 

psyco_guy_abd

New member
You can do the same thing without all the elbows and airlines, I run two stand pipes in my 75 w/ external overflow. They are both 1 1/4", one is wide open and adjusted so normally no water (ok maybe only a trickle) goes through it. This one is the same hight as my overflow cut outs. The second pipe is about 3" tall and has a gate valve on it. I adjust the gate valve so that the top of this pipe is fully submerged (no noise). The way this works is that the primary pipe flows all of the water, plus there is about 6" between the top of it and the top of emergency (open) stand pipe. This lets it build a little head pressure to compensate for things like the depth of the water in the sump, pump efficiency, and small clogs. Worst case is that the primary pipe gets plugged up totally and all the flow goes down the backup before it overflows my tank.
 

sscheitel

New member
"one is wide open and adjusted so normally no water (ok maybe only a trickle) goes through it. "

How are you adjusting this? with a valve on the return pump?
 

sscheitel

New member
Also I need to claify....this will be an INTERNAL overflow...I failed to mention that. It does not change much of the details...just wanted to let you guys know.
 

psyco_guy_abd

New member
Sorry, I guess I didn't explain that very well. I have two pipes, the lower one is partially closed with a gate valve. The taller one is wide open, it has no restrictions. I adjust the level of the water in the overflow with the valve on the lower pipe, the more I close it off the higher the water level gets until it starts to overflow into the taller pipe.
 

BeanAnimal

Premium Member
<a href=showthread.php?s=&postid=9874651#post9874651 target=_blank>Originally posted</a> by Randall_James
The idea behind the overflow is to capture only the very top layer of water off the tank and to keep this effluent as concentrated as possible. This effluent should match as close as possible to 100% of skimmer flow (Ideally 2 skimmers and they are cleaned on alternate days) Running this effluent to an area that feeds only the skimmer is also suggested. (these are the suggestions by A.Calfo)

Running this overflow for the closed loop will only serve to dilute the effluent and make the skimmers work harder to get the DOS out. (if you drop a note to Anthony, he will be more than happy to respond btw, probably worth the few minutes it takes)

For starters... Anthony is a local club member (one of the founders) and a friend. We have talked about this subject several times.

Yes returning the effluent back to the tank without skimming it increases the chances of it being used in the tank instead of being skimmed.

However, there is a LOT more to it than that. Sizing the skimmer to handle ALL of the overflow water is one thing. However, most folks only skim a small fraction of the water with each pass through the sump. Why move the water through the sump with the net loss of energy due to head and friction, when you can move it via a closed loop?

I feed my skimmer from closed a closed loop (via the overflow) and the refugium with a second closed loop. This is in addition to the the 1500 GPH that goes through the sump.

I would agree that pushing the loop water over the overflow weir is not the ideal situation, but in perspective with the size and scale of the overflow, it is certainly not a problem.

In my case there is a large portion of LR in the sump with a "cryptic zone" and detritus settling area. The sump is high flow to support these "zones".

My "flow" closed loop is NOT fed from the overflow.

There are a lot of ways to skin a cat.
 

BeanAnimal

Premium Member
<a href=showthread.php?s=&postid=9874755#post9874755 target=_blank>Originally posted</a> by sscheitel
Thank You all for the input.

Bean,
If the power goes out...will #2 (full siphon) prime itself without me doing anything?

....also....as long as I am driving enough water to the sump and not returning more than the bulkheads can handle...why do I need the guest valves? and why the full siphon.

I currently have a 90 gal - 1" bulkhead w/durso stand pipe...no john guest valve...running a MAG 9.5...the bulkhead is more than capable of the flow that the 9.5 is returning. The result is a quiet overflow. As long as I stick to this principle...why do I need the full siphon on #2?

I love the idea of the upturned 90 degree elbow for emergency blockage. I will definetly be making a 4th drilled hole for this.

Well...hit me with your thoughts....

Thanks

Yes, the may rise high enough to spill over into the emrgency overflow for a brief moment until the siphon kicks in.

The full siphon is what makes the "system" work silently and without air entrainment.

The full siphon is dead silent and adjusted to NOT handle ALL of the flow. The second standpipe handles the excess and allows the full siphon to "self tune". No gurgles, no pain in the butt dursos or other nonsense. No air in the sump etc.

Trust me.. this is magnitudes better than a "Durso" or "stockman" setup. Lets put it this way... build your "dursos" and instead of drilling "air holes" put the valves in place and give it a try.

Also, this setup will handle MUCH more flow than a set of dursos (not an issue for you, but nonetheless a benefit).

Remember you want the upturned elbow to be sealed so that it will siphon (it will flush like a toilet, but will prevent floods). If it is not setup to siphon it will not likely handle ALL of the flow if ever needed to.


Bean
 

BeanAnimal

Premium Member
<a href=showthread.php?s=&postid=9875368#post9875368 target=_blank>Originally posted</a> by psyco_guy_abd
You can do the same thing without all the elbows and airlines, I run two stand pipes in my 75 w/ external overflow. They are both 1 1/4", one is wide open and adjusted so normally no water (ok maybe only a trickle) goes through it. This one is the same hight as my overflow cut outs. The second pipe is about 3" tall and has a gate valve on it. I adjust the gate valve so that the top of this pipe is fully submerged (no noise). The way this works is that the primary pipe flows all of the water, plus there is about 6" between the top of it and the top of emergency (open) stand pipe. This lets it build a little head pressure to compensate for things like the depth of the water in the sump, pump efficiency, and small clogs. Worst case is that the primary pipe gets plugged up totally and all the flow goes down the backup before it overflows my tank.

The down turned elbows make it harder for "stuff" to get into the sump. :)
 

sscheitel

New member
Bean

So standpipe #1 is actually a durso pipe...no? open full...air valve open full

Are standpipes #1 & 2 the same height? How will I know when stand pipe #1 is getting some of the flow?

Can I not use a manifold?
I wanted to channel all 3 hoses into a 3" 3-Way PVC pipe before it hits the sump.
 
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Randall_James

Premium Member
For starters... Anthony is a local club member (one of the founders) and a friend. We have talked about this subject several times.
good for you, you should ask his opinion about running 20X to 50X through the same overflow you are feeding your skimmer from

I am saying that the surface water contains a high percentage of the dissolved organics and the more of this that goes through the skimmer undiluted the better. (you can measure skimmer performance and output to see this for yourself)

I never suggested the use of sump flow for tank flow nor would I. it is just asking for trouble...

Now the mechanics of that water flow..

If you take that 3x to 5x flow rate that is only surface water, and dilute it with the the 20X-50X of closed loop flow, you have just reduced the concentration of the dissolved organics by that same amount. (if you feed the closed loop from the overflow box, you have just done this and much of that dirty water will never see the skimmer or sump, it just got recirculated back into the water column and must be removed later)

The skimmer must now process up to 10X's more water to even come in contact with those same organics. Closed loop is much better fed by a supply below the water line and not in the overflow box itself. I would be more inclined to add a forth hole outside overflow box and draw my closed loop water from somewhere else. I have tested this and you can too. Your skimmer will produce less effluent if you increase the flow through the tank overflow like that.

Anthony has stated many times that the more concentrated you keep this skimmer feed the better off you are. He goes as far as to suggest you run your overflow water into a bucket or like containment setup in your sump and feed your skimmer exclusively from this chamber. (if you do this, you will see an increase in skim-mate as well) There is an old thread here on RC about skimmer performance and how to beef it up. It is a LONG read but has a lot of very good information as well as lots of things that have been tried.
 
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BeanAnimal

Premium Member
<a href=showthread.php?s=&postid=9881571#post9881571 target=_blank>Originally posted</a> by Randall_James
good for you, you should ask his opinion about running 20X to 50X through the same overflow you are feeding your skimmer from
Why be a jerk Randall? You posted as if I was uninformed and used an a well respected member of the community to back up your point. That expert happens to be a friend... I simply pointed that out. I also pointed out that we have talked about this exact subject many times. Your certainly twisting this out of context.. but hey whatever makes you happy.

I am saying that the surface water contains a high percentage of the dissolved organics and the more of this that goes through the skimmer undiluted the better. (you can measure skimmer performance and output to see this for yourself)
Nobody said that was not true Randall. That is the whole basis of increasing overflow length to aid in surface skimming. That is the whole basis for feeding a skimmer directly from the overflow. Your not the only person who understands that Randall.

I never suggested the use of sump flow for tank flow nor would I. it is just asking for trouble...
I never said you did. In some situations it is certainly NOT asking for trouble. The problem here is that you are taking a concept and using it as a broad brush to paint everything. There are setups that are nearly ideal and setups that make concessions in one aspect or another. This depends on the tank size, equipment on hand, space and aesthetic considerations etc. In my case, a LOW FLOW sump is not really an option based upon several of my design goals and associated limitations. For another person a low flow sump may be a very smart choice.

Now the mechanics of that water flow..
No offense Randall, but I certainly do not need a flip lesson from you on water flow mechanics.

If you take that 3x to 5x flow rate that is only surface water, and dilute it with the the 20X-50X of closed loop flow, you have just reduced the concentration of the dissolved organics by that same amount. (if you feed the closed loop from the overflow box, you have just done this and much of that dirty water will never see the skimmer or sump, it just got recirculated back into the water column and must be removed later)
What a revaluation! Did I not just say that?

The skimmer must now process up to 10X's more water to even come in contact with those same organics. Closed loop is much better fed by a supply below the water line and not in the overflow box itself.
Are you sure about that Randall. You certainly left a LOT of mechanics out. Is the skimmer processing 100% of the water in the overflow? Is there a Sump? What is the sump turnover rate? What is the skimmers feed rate? What is the CL feed rate? TIME is part of the equation also. Have you considered the concentrations per pass? The WATTS per pass either in the closed loop, sump, skimmer etc?

The efficiency of any two setups will differ... But will they differ enough to make a design choice based on that efficiency? The point was that there are more ways to skin a cat than the "ideal". Each method has pros and cons. That's all. Did I not also say (infer) that feeding the CL from the overflow box may NOT be ideal, but may be a reasonable way to feed other equipment and still get decent skimming while meeting other design goals?

THE POINT RANDALL WAS that there are several ways to achieve good skimming and still not follow the strict principles you have outlined. In the OPS case the surface skimming would be great. However running a closed loop for some added flow or to feed a refugium is certainly NOT going to destroy the efficiency of they system.

I would be more inclined to add a forth hole outside overflow box and draw my closed loop water from somewhere else. I have tested this and you can too. Your skimmer will produce less effluent if you increase the flow through the tank overflow like that.
Nobody said it wouldn't. I feed my flow closed loop from below the skimmer box just for that reason. I feed the refugium and skimmer FROM the overflow via closed loops FOR THAT REASON.

If I were to do it all over, I may change some things, but I certainly would not lose the high flow sump (I can list many reasons why).

Anthony has stated many times that the more concentrated you keep this skimmer feed the better off you are. He goes as far as to suggest you run your overflow water into a bucket or like containment setup in your sump and feed your skimmer exclusively from this chamber. (if you do this, you will see an increase in skim-mate as well)
There is an old thread here on RC about skimmer performance and how to beef it up. It is a LONG read but has a lot of very good information as well as lots of things that have been tried.
Yes, I have read the thread as well as had the discussion in persons several times. Nobody (at least me) is in disagreement. Many of the principles were used in the setup of my own system.

Feeding the skimmer directly from overflow water is almost ideal. Matching the skimmers size to the overflow rate and feeding 100% of it to the skimmer is even more ideal. I already acknowledged that.
 

BeanAnimal

Premium Member
<a href=showthread.php?s=&postid=9879625#post9879625 target=_blank>Originally posted</a> by sscheitel
Bean

So standpipe #1 is actually a durso pipe...no? open full...air valve open full

Are standpipes #1 & 2 the same height? How will I know when stand pipe #1 is getting some of the flow?

Can I not use a manifold?
I wanted to channel all 3 hoses into a 3" 3-Way PVC pipe before it hits the sump.

I suppose you could call it a durso...

However as an added safety, I add rigid airline to the the valve and curl it back over, clamping it's opening just below the tip of the trim (in the critical water height zone).

If the water ever gets that high it will block the air vent and turn #1 into a siphon also. So between it and the emergency overflow, you have a double failsafe :)

#1 and #2 are identicle other than the valve positions. I add the air valve and ball valve to all 3 standpipes, so any can perform any function.

You will close the ball valve down on #2 until the water level rises in the overflow box and #2 stops flushing or gurgling. From that point the further you close it, the more flow will be handled by #1. You want to find a happy medium. Too much water through #1 and it will start to pull air down with it (LIKE A DURSO). You want that water to cascade down and pull very little air.

Too little flow through #1 and the siphon will always be on the verge of sucking air because it is almost directly matched with 100% of the return pump flow.

It sounds more complicated than it really is.

Just close the valve down until things work... It will self tune from there. Once in a while you need to open the valve and let it flush any debris out. You will know when this needs to happen based on the water level in the overflow box rising well above your normal set point. (I do mine every month or so... maybe less).

Back when I had dursos... I was constantly having to tweak them. I had a ton of air in the sump and they were quiet, but not silent.
 

friendorfoe

New member
I am liking this overflow setup here. one thing though, you have hole drilled into back of tank, back of box, how are you securing box to tank without the fear of water leaking? From my understanding, the bulk head is whats securing box to back of tank. what about the space between box and tank,I know tank should be staight but some of us have older tanks and there may just be a minute space, is there anyway to eliminate that?
 
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