corner calfo overflow
- Thread starter RobertK
- Start date
BeanAnimal
Premium Member
Robert.. I am not sure that your qeustion makes sense... let me see if I can help. When poeple refer to a "calfo" style overflow, they are simply refering to a "coast-to-coast" style overflow where the back wall of the tank is fitted with an internal overflow shelf that runs THE LENGTH of the tank. The main design principle being the maximized linear overlfow distance, not the physical construction of the overlow, which by default usually ends up being a shelf to conserve space and minimize water volume this maximizing protien concentration.
A corner overflow... is well, a corner overflow
Making it shallow will save space int the tank and maximize the protien concentration in the overflow water. However you negate the main benefit (the linear overflow distance).
I hope that helps...
Bean
A corner overflow... is well, a corner overflow
Making it shallow will save space int the tank and maximize the protien concentration in the overflow water. However you negate the main benefit (the linear overflow distance).I hope that helps...
Bean
RobertK
Premium Member
Hi Bean,
Thanks for the reply. Yes, I am very familiar with the concept of the "calfo overflow". Actually, it was Anthony Calfo who suggested that I convert my vertical corner overflow into a "horizontal corner overflow" by adding a horizontal section on top of it that would extend some distance out from the corner, thus increasing the width of the surface that overflows. See his reply midway down page 8 of the following thread (right after the picture of my overflow):
click here
He suggested that I search the forums here for an example of such a design, but I could find none, so I thought I'd ask.
Thanks for your interest,
Robert
Thanks for the reply. Yes, I am very familiar with the concept of the "calfo overflow". Actually, it was Anthony Calfo who suggested that I convert my vertical corner overflow into a "horizontal corner overflow" by adding a horizontal section on top of it that would extend some distance out from the corner, thus increasing the width of the surface that overflows. See his reply midway down page 8 of the following thread (right after the picture of my overflow):
click here
He suggested that I search the forums here for an example of such a design, but I could find none, so I thought I'd ask.
Thanks for your interest,
Robert
BeanAnimal
Premium Member
Ahh the pictures of your delima help quite a bit.
I have assumed you understood the idea, but I have provided clarification just in case. No, I have not seen anybody do this.. but it is fairly straightforward and better than what you have and avoids the limitation of your glass braces.
What anthony has suggest you do is very simple. Cut the overlfow you have down in height... say an inch or 3 below the bottom of the teeth. Fashion a piece of glass or acrylic to cover that edge in a horizontal fashion and then add a vertical section to create a new weir. The new weir should be flat with no teeth... teeth are eyecandy and a waste of time.
Here is a top view, the old corner overflow is on the left, the new on the right. The green colored piece is the new bottom and the red line indicates the new vertical piece that forms the weir. The top of the weir should be where you want the min water level to be... we usually set them at the bottom edge of the trim.
Does that help?
I have assumed you understood the idea, but I have provided clarification just in case. No, I have not seen anybody do this.. but it is fairly straightforward and better than what you have and avoids the limitation of your glass braces.
What anthony has suggest you do is very simple. Cut the overlfow you have down in height... say an inch or 3 below the bottom of the teeth. Fashion a piece of glass or acrylic to cover that edge in a horizontal fashion and then add a vertical section to create a new weir. The new weir should be flat with no teeth... teeth are eyecandy and a waste of time.
Here is a top view, the old corner overflow is on the left, the new on the right. The green colored piece is the new bottom and the red line indicates the new vertical piece that forms the weir. The top of the weir should be where you want the min water level to be... we usually set them at the bottom edge of the trim.
Does that help?
RobertK
Premium Member
Thank you, Bean. That does help. Coupla things -
I do think this ought to work (after all, Anthony said so), but am feeling very sheepish about cutting down the existing overflow - that is so irreversible. I'm wondering if I can just slap on the new contraption with silicone and have the water flow through the teeth in the existing overflow.
About the floor of the new part - does it need to slope downward toward the corner or will flat be OK?
Thanks again,
Robert
I do think this ought to work (after all, Anthony said so), but am feeling very sheepish about cutting down the existing overflow - that is so irreversible. I'm wondering if I can just slap on the new contraption with silicone and have the water flow through the teeth in the existing overflow.
About the floor of the new part - does it need to slope downward toward the corner or will flat be OK?
Thanks again,
Robert
BeanAnimal
Premium Member
Well... the teeth are the limiting factor now for surface skimming. Slapping this on and leaving the teeth will allow MORE flow over the weir, but the teeth may present a problem. You could always use a dremel to cut them away if they become a problem I guess. Flat should be fine.... sloped would be better. Better get the geometry book out... sloped will increase the right angle at the corners in the obtuse direction (+90) I guess you could just make it like 94 and tilt it till it fits wherever that is!
BeanAnimal
Premium Member
He can't run it across the back.. he has a eurobrace that is very much in the way.
RobertK
Premium Member
Bean,
My geometry sucks. I can handle 45 and 90 degrees, but that's about it. If a flat-bottomed contraption will work then I'll go with it.
wadomas,
Yes, I've tried to think of a way to do that, given the limitations of my tank. I thought about rigging up a trough with a weir that would run along the back, somehow clamp onto the eurobrace, drop in height from left to right and dump into a hole cut into the existing tower, but the whole concept was too complicated and the design/installation too daunting for me. So I've pretty much given up on it. The modification I'm considering now could be made out of four pieces of acrylic.
Bean,
waldomas asks a very good question: "Is that set-up really going to make a big difference?" What do you think? The goal, of course is to increase the efficiency of the skimmer.
Thanks,
Robert
My geometry sucks. I can handle 45 and 90 degrees, but that's about it. If a flat-bottomed contraption will work then I'll go with it.
wadomas,
Yes, I've tried to think of a way to do that, given the limitations of my tank. I thought about rigging up a trough with a weir that would run along the back, somehow clamp onto the eurobrace, drop in height from left to right and dump into a hole cut into the existing tower, but the whole concept was too complicated and the design/installation too daunting for me. So I've pretty much given up on it. The modification I'm considering now could be made out of four pieces of acrylic.
Bean,
waldomas asks a very good question: "Is that set-up really going to make a big difference?" What do you think? The goal, of course is to increase the efficiency of the skimmer.
Thanks,
Robert
BeanAnimal
Premium Member
Yes it will make a difference... your "linear overflow" length is the sum distance of the space BETWEEN the teeth minus maybe 5% (due to the surface tension at each tooth interface)
So lets say your box is 6 inches by 6 inches with 1/4" gaps and 1/4" teeth. That is a sum total of less than 6" of linear overflow.
remember A^2 + B^2 = C^2 So lets say you make the diagonal touch the outer corner of the existing intake box. That leaves 2 right triangles (1 to the left and one to the right of the box). The box is 6" and the triangles are "right triangles" that means that both legs are equal in lenght. So we want to know how long the hypotenuse is.
That is
6^2+6^2 = hypotenuse ^2
or
36 + 36 = C^2
or
72 = C^2
or
C=sqrt(72)
or
8.48 inches
Now we have (2) such right triangles so we have just under 17 inches of linear overflow from tank wall to tank wall (the length of the RED line above).
In a similar fashion, from the above geometry we can see that we have 1 BIG right triangle formed by the corner of the tank and the RED line. Look closely and remember geometry class. The length of the legs is 12" (if the overlfow box is 6" by 6") So lets say you want a bit more linear overflow... lets move the red line out to meet a point that is 13" from each corner instead of 12"
So we have a right triangle that is 13" by 13"
or
13^2 + 13^2 = C^2
which solves to a hyptenuse of 18.38"
Help?
So lets say your box is 6 inches by 6 inches with 1/4" gaps and 1/4" teeth. That is a sum total of less than 6" of linear overflow.
remember A^2 + B^2 = C^2 So lets say you make the diagonal touch the outer corner of the existing intake box. That leaves 2 right triangles (1 to the left and one to the right of the box). The box is 6" and the triangles are "right triangles" that means that both legs are equal in lenght. So we want to know how long the hypotenuse is.
That is
6^2+6^2 = hypotenuse ^2
or
36 + 36 = C^2
or
72 = C^2
or
C=sqrt(72)
or
8.48 inches
Now we have (2) such right triangles so we have just under 17 inches of linear overflow from tank wall to tank wall (the length of the RED line above).
In a similar fashion, from the above geometry we can see that we have 1 BIG right triangle formed by the corner of the tank and the RED line. Look closely and remember geometry class. The length of the legs is 12" (if the overlfow box is 6" by 6") So lets say you want a bit more linear overflow... lets move the red line out to meet a point that is 13" from each corner instead of 12"
So we have a right triangle that is 13" by 13"
or
13^2 + 13^2 = C^2
which solves to a hyptenuse of 18.38"
Help?
mr.wilson
.Registered Member
It would be easier to address the route of your problem, rather than reinventing the wheel. You have surfactants collecting at the surface that aren't getting skimmed. This is due to the fact that your return line is directing water away from the overflow, rather than toward it.
If you relocate your return line to the opposite end of the tank, it will push the water over the overflow. Your current configuration is sucking water from below the surface. You can test this with flake food at the surface. You will be able to see the flakes remain at the surface while other particles are drawn from below the teeth.
Once you stop the return (or closed loop) flow in front of your corner overflow, it will start to suck from the surface and draw surfactants from a greater area. You still have the same net amount of surface movement, just better coordinated so the pump is pushing, and the overflow is sucking. Both need to be designed so they work together.
In some cases it's just a matter of directing the pump flow down, so the overflow can draw from the surface. These minor changes can effect a significant change in flow dynamics.
If you're leery about making drastic changes, use an extension hose on the return line (temporarily) to test my recommendations. Do the flake food test and see if it all gets skimmed. You should be able to dial it in with no changes to your existing overflow.
Another test of my theory is to turn the return pump off for a few minutes. You will note that the surface skimmer has no problem drawing from the surface even before the water level drops.
I like the use of teeth, as it keeps shrimp and small fish out of the overflow plumbing & sump. As long as you have good surface agitation, there is less surface tension, and better surface skimming.
If you relocate your return line to the opposite end of the tank, it will push the water over the overflow. Your current configuration is sucking water from below the surface. You can test this with flake food at the surface. You will be able to see the flakes remain at the surface while other particles are drawn from below the teeth.
Once you stop the return (or closed loop) flow in front of your corner overflow, it will start to suck from the surface and draw surfactants from a greater area. You still have the same net amount of surface movement, just better coordinated so the pump is pushing, and the overflow is sucking. Both need to be designed so they work together.
In some cases it's just a matter of directing the pump flow down, so the overflow can draw from the surface. These minor changes can effect a significant change in flow dynamics.
If you're leery about making drastic changes, use an extension hose on the return line (temporarily) to test my recommendations. Do the flake food test and see if it all gets skimmed. You should be able to dial it in with no changes to your existing overflow.
Another test of my theory is to turn the return pump off for a few minutes. You will note that the surface skimmer has no problem drawing from the surface even before the water level drops.
I like the use of teeth, as it keeps shrimp and small fish out of the overflow plumbing & sump. As long as you have good surface agitation, there is less surface tension, and better surface skimming.
BeanAnimal
Premium Member
While I agree that changing the flow pattern will help, it still does not address the problem of insufficient surface skimming. The teeth cut what is already there down by at least 50%. The funny part is, most shrimp and fish can go through the teeth just as easily as they can go over a flat weir. That said, on a very short overflow, the weir depth can be rather substantial and force the use of teeth, but that goes back to the lack of linear overflow lenght and the need to address the problem.
It has beeh shown that the larger the weir length, the better the surface skimming due to the thinner sheet of water flowing over the weir. The protien layer is molecules thick and covers the surface of the water due to the air/water contact and surface tension. The faster we can move this "sheet" the more protiens we move away from the display and the less chance they have of becoming absorbed by the system.
It has beeh shown that the larger the weir length, the better the surface skimming due to the thinner sheet of water flowing over the weir. The protien layer is molecules thick and covers the surface of the water due to the air/water contact and surface tension. The faster we can move this "sheet" the more protiens we move away from the display and the less chance they have of becoming absorbed by the system.
mr.wilson
.Registered Member
I agree that a larger overflow interface will skim a thinner layer of surface water; however, this function is only necessary with still water of greater surface tension. There's no need for a coast to coast overflow if you implement proper flow dynamics. Even with a modest overflow with teeth, any and all hydrophobes that collect at the surface, will still be exported to the sump efficiently.
It's a given that teeth greatly diminish the interface area, and increase surface tension, but as long as complete removal of surface film is achieved, teeth can remain to serve their purpose. Curious fish and invertebrates will find a way into an overflow box, but teeth certainly discourage them.
A still surface with a large overflow interface can remove a very thin layer of film, but this necessity is a byproduct of its' own design. Still water at the surface will attract more surfactants, due to an increased dwell time, and stability. Poorly engineered flow dynamics accelerate this process, as dead spots occur in various locations at the surface. A thin film of hydrophobes are trapped in limbo with nowhere to go, regardless of overflow interface size or design.
There are no benefits to having limited surface agitation. Any hydrophobic agents that are collected at the surface of the tank still need to be bonded to air bubbles in the protein skimmer in order to be exported. There is far greater air/water interface in the protein skimmer, so focusing on the surface interface of the display tank for this function is counter-productive. the reason why I bring up this point, is because I've seen a few aquariums where the owners severely resticted surface flow, in order to skim the resulting surface film. An ouroboras (snake that eats its' own tail) of sorts.
The other factor that comes into play is the wave action that impedes with a coast to coast overflows' ability to skim directly from the surface. If you don't address the route of the problem (flow patterns), there's no overflow size or design that can solve it.
The problem at hand here is pockets of surfactants that aren't being skimmed by the overflow. I maintain that the problem can be solved by having the primary return line at the opposite end of the tank, directed across the surface toward the overflow. A secondary return line can be located at the same end as the overflow, directed down at a 45 degree angle. A simple test using floating flake food will demonstrate how quickly it exits the display tank, via the overflow.
A greater function of collecting POC, while maintaining maintaining the ability to remove surfactants, can be served with this type of flow configuration.
It's a given that teeth greatly diminish the interface area, and increase surface tension, but as long as complete removal of surface film is achieved, teeth can remain to serve their purpose. Curious fish and invertebrates will find a way into an overflow box, but teeth certainly discourage them.
A still surface with a large overflow interface can remove a very thin layer of film, but this necessity is a byproduct of its' own design. Still water at the surface will attract more surfactants, due to an increased dwell time, and stability. Poorly engineered flow dynamics accelerate this process, as dead spots occur in various locations at the surface. A thin film of hydrophobes are trapped in limbo with nowhere to go, regardless of overflow interface size or design.
There are no benefits to having limited surface agitation. Any hydrophobic agents that are collected at the surface of the tank still need to be bonded to air bubbles in the protein skimmer in order to be exported. There is far greater air/water interface in the protein skimmer, so focusing on the surface interface of the display tank for this function is counter-productive. the reason why I bring up this point, is because I've seen a few aquariums where the owners severely resticted surface flow, in order to skim the resulting surface film. An ouroboras (snake that eats its' own tail) of sorts.
The other factor that comes into play is the wave action that impedes with a coast to coast overflows' ability to skim directly from the surface. If you don't address the route of the problem (flow patterns), there's no overflow size or design that can solve it.
The problem at hand here is pockets of surfactants that aren't being skimmed by the overflow. I maintain that the problem can be solved by having the primary return line at the opposite end of the tank, directed across the surface toward the overflow. A secondary return line can be located at the same end as the overflow, directed down at a 45 degree angle. A simple test using floating flake food will demonstrate how quickly it exits the display tank, via the overflow.
A greater function of collecting POC, while maintaining maintaining the ability to remove surfactants, can be served with this type of flow configuration.
BeanAnimal
Premium Member
With all due respect, I beg to differ, as the science and research on the subject show differently. There are numerous threads here at RC on the subject as well as at other similar venues that site several different studies and/or scientific explanations that explain the mechanics. There is no need to beat a dead horse once again.
Sir Given the same flow, a larger wier removes more of the water at the surface interface FASTER. The faster the interface is removed (NOT CHURNED BACK IN) the faster new protiens can be attacted to the air/water interface. This is simple physics and can be shown with OIL at the surface or aerated into the tank.
Regardless, the longer weir facilitates quicker surface turnover INTO THE WEIR instead of backinto the captive body. This holds true in all cases. Dead spots, poor flow or not.
That is a very broad assumption. Firstly, they protiens don't even have a chance to be skimmed unless they make it to the skimmer. Secondly, you are assuming that the molecular bond from the surface skim is the same as that of the deeper water. Very simple proof that your theory is wrong. Place a skimmer in the tank and one inline with the overlfow water. The skimmer inline with the overlfow water will always outperform the in tank skimmer. Why? The surface water has a higher concentration of protiens in it and some have already been partially broken down due to the air/water interface contact.
Again, that is a problem with ANY design and not a handicap for a longer weir. Given the same poor flow characteristics, the longer weir will still outperform the shorter weir.
We can go on and on with this.... I respect your opinion but simply do not find the physics or science that fits it. You are advocating good flow direction and saying that the longer overlfow is not needed. In other words you have picked an arbitrary point and said "any longer than that is a hinderance, not a help". I do feel that there is a point of diminishing returns but don't see it being anywhere near the length of a typical "coast to coast" overflow.
I have enjoyed this discussion... but honestly don't think we are going to get much further
Regards,
Bean
mr.wilson
.Registered Member
<a href=showthread.php?s=&postid=8812696#post8812696 target=_blank>Originally posted</a> by BeanAnimal
I have enjoyed this discussion... but honestly don't think we are going to get much further
Regards,
Bean
Well that saves a lot of trouble.
Let us know how it works out Robert.
RobertK
Premium Member
Wow, thanks for all the input! I was away for xmas and unable to reply. You've all given me a lot of food for thought and I appreciate it greatly.
Bean: Your diagram and calculations were very helpful - thanks for taking the trouble. I hadn't considered the fact that the teeth were cutting down on the surface skimming so much. My plan (I think) is to use a toothless design for the modification, but to attach some plastic mesh gutter guard to the inside of it to keep larger critters out of the overflow. I did have an incident a year or so back in which a snail found its way into the overflow, partially blocked the standpipe, causing the water level in the sump to drop and my topoff system to malfunction, in turn dumping 5 gallons of kalkwasser into the tank. It nearly wiped out the whole system. I quit dosing kalk after that and switched to B-ionic instead, but I am still very wary about things getting into the overflow.
mr.wilson: My flow dynamics are not optimal due the design of my tank, which I am embarassed to say was designed by yours truly years ago when I was quite naive about such things. But for now I am stuck with it. The euro brace goes all around the tank but is only drilled right next to the overflow. Coupla things the picture doesn't show: The return line is 3/4" locline that drops down about a foot into the tank and then turns left about 8". There is nothing up against the back wall of the tank and the return water is directed in such a way that that the surface does not appear to be greatly affected. There is also a large Tunze Stream pump located below the overflow (and yes, directing water away from it), which agitates the surface somewhat and keeps many particles in suspension. I initially had it placed on the opposite end of the tank for the exact reason you stated, but it created a dead spot of surface film that was trapped in the corner behind it, so I moved it to the overflow side and there are no visible dead spots now. Due to the size of the Tunze and that of the tank there are really no other places to put it. I do plan to change to two Tunze Nanostreams soon, which should give me more flexibility in their placement. I have tinkered with these factors a lot in an effort to get the best out of the system that I can, given its limitations, and to eliminate any visible dead spots on the surface as much as possible. I will try the flake food test you suggested to see if that gives me any more ideas.
Thanks again for all the input and the healthy debate. I will re-read your replies a few more times to digest the ideas you have put forth, and will let you know how it goes.
Robert
Bean: Your diagram and calculations were very helpful - thanks for taking the trouble. I hadn't considered the fact that the teeth were cutting down on the surface skimming so much. My plan (I think) is to use a toothless design for the modification, but to attach some plastic mesh gutter guard to the inside of it to keep larger critters out of the overflow. I did have an incident a year or so back in which a snail found its way into the overflow, partially blocked the standpipe, causing the water level in the sump to drop and my topoff system to malfunction, in turn dumping 5 gallons of kalkwasser into the tank. It nearly wiped out the whole system. I quit dosing kalk after that and switched to B-ionic instead, but I am still very wary about things getting into the overflow.
mr.wilson: My flow dynamics are not optimal due the design of my tank, which I am embarassed to say was designed by yours truly years ago when I was quite naive about such things. But for now I am stuck with it. The euro brace goes all around the tank but is only drilled right next to the overflow. Coupla things the picture doesn't show: The return line is 3/4" locline that drops down about a foot into the tank and then turns left about 8". There is nothing up against the back wall of the tank and the return water is directed in such a way that that the surface does not appear to be greatly affected. There is also a large Tunze Stream pump located below the overflow (and yes, directing water away from it), which agitates the surface somewhat and keeps many particles in suspension. I initially had it placed on the opposite end of the tank for the exact reason you stated, but it created a dead spot of surface film that was trapped in the corner behind it, so I moved it to the overflow side and there are no visible dead spots now. Due to the size of the Tunze and that of the tank there are really no other places to put it. I do plan to change to two Tunze Nanostreams soon, which should give me more flexibility in their placement. I have tinkered with these factors a lot in an effort to get the best out of the system that I can, given its limitations, and to eliminate any visible dead spots on the surface as much as possible. I will try the flake food test you suggested to see if that gives me any more ideas.
Thanks again for all the input and the healthy debate. I will re-read your replies a few more times to digest the ideas you have put forth, and will let you know how it goes.
Robert
mr.wilson
.Registered Member
It looks like you're going to have to get wet and test some combinations before you commit to ant permanent changes.
I still maintain, that unless you fix your flow pattern issues, the surface film will continue to haunt you, regardless of overflow design.
One possible solution for the dead spot above the Tunze (in the old position, opposite from the overflow), is to lower the powerhead a few inches and aim it up at a 45 degree angle. This may cause subtle splashing issues, but it would pull the still water from behind/above it.
Another experiment would be to direct flow against the wall beneath the Tunze (in the old position, opposite from the overflow). This may break surface tension and give you a circular motion.
The problem you will find with mesh on the overflow is that it will give you the same result as teeth (greater surface tension, inhibited draining).
You could go with a toothless overflow and use a parallel divider spaced 1/4" behind it. The display water would overflow the first wall and travel under the second, parallel wall. You would have free flow over the first wall, while maintaining a barrier for interlopers with the second. The parallel wall could be constructed of mesh, eggcrate or glass/acrylic. Bioballs with a large void space such as Tripack spheres and tellerette rings also work as a barrier without inhibiting overflow.
The only problem with this barrier system is that, unlike teeth, it allows critters to get trapped in limbo.
I still maintain, that unless you fix your flow pattern issues, the surface film will continue to haunt you, regardless of overflow design.
One possible solution for the dead spot above the Tunze (in the old position, opposite from the overflow), is to lower the powerhead a few inches and aim it up at a 45 degree angle. This may cause subtle splashing issues, but it would pull the still water from behind/above it.
Another experiment would be to direct flow against the wall beneath the Tunze (in the old position, opposite from the overflow). This may break surface tension and give you a circular motion.
The problem you will find with mesh on the overflow is that it will give you the same result as teeth (greater surface tension, inhibited draining).
You could go with a toothless overflow and use a parallel divider spaced 1/4" behind it. The display water would overflow the first wall and travel under the second, parallel wall. You would have free flow over the first wall, while maintaining a barrier for interlopers with the second. The parallel wall could be constructed of mesh, eggcrate or glass/acrylic. Bioballs with a large void space such as Tripack spheres and tellerette rings also work as a barrier without inhibiting overflow.
The only problem with this barrier system is that, unlike teeth, it allows critters to get trapped in limbo.
RobertK
Premium Member
I thought the mesh would be somewhat of a compromise, since it allows much more water flowthrough than the teeth.
I will definitely get wet and try out different placements of the new Nanostreams when I get them. I don't think the big Tunze that I have now will tilt up, only right and left. I think the Nanostreams are more versatile.
Thanks again,
RK
I will definitely get wet and try out different placements of the new Nanostreams when I get them. I don't think the big Tunze that I have now will tilt up, only right and left. I think the Nanostreams are more versatile.
Thanks again,
RK
RobertK
Premium Member
Well, I finally did it. It took a lot of measuring and tinkering, but it works.
Here is what it looked like before:
old overflow from above
old overflow from below
Here is what it looks like now:
new overflow, return pump off
new overflow from above
new overflow from below
The new weir is 17" long, roughly 5 times longer than the combined widths of the 10 teeth in the old overflow. The stream of water over the new weir is 0.2" deep, compared with 0.625" deep through the old teeth.
I got two new Tunze nanostreams and the flow pattern is now good. Flake food dropped on the left side of the tank goes straight over to the right side and over the falls.
Still can't tell if the skimmer is working any better, though. It's been set up like this for a week.
Thanks again for all the help planning this thing.
Robert
Here is what it looked like before:
old overflow from above
old overflow from below
Here is what it looks like now:
new overflow, return pump off
new overflow from above
new overflow from below
The new weir is 17" long, roughly 5 times longer than the combined widths of the 10 teeth in the old overflow. The stream of water over the new weir is 0.2" deep, compared with 0.625" deep through the old teeth.
I got two new Tunze nanostreams and the flow pattern is now good. Flake food dropped on the left side of the tank goes straight over to the right side and over the falls.
Still can't tell if the skimmer is working any better, though. It's been set up like this for a week.
Thanks again for all the help planning this thing.
Robert
