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Glass Cage warranty........
- Thread starter Yaktop
- Start date
RichConley
Attack of the Killer Cute
If you move the whole tank back and forth, then you ARE making the tank side stop all 50 gallons of water. 50 gallons gets accelerated to the right, then when the glass tank is stopped and moved the other way, 50 gallons has to stop moving right, and turn around to accelerate to the left. That's a lot of force. But with a Wave box, the only NET movement of weight (it would seem to me) is a couple gallons in a tank that size, since everything stays in place except that the water level on one end goes up an inch, and the other end falls an inch. The glass only has to absorb the force of the net amount of water that's actually switching sides. If the force were relative to the gross amount of water moving in the tank, then even a simple power head would cause thousands of pounds of pressure against the side of the tank (but in reality, the exact same weight of water shot out of a powerhead is also moving in the opposite direction towards the powerhead, so there is no net acceleration of water against the end of the tank.
Ok. Now the physicists can step in and have a field day with my explanation.
Exactly Nate.
Steve, yes, you are moving more water, but that isnt causing any stress on the glass. If moving water caused seam stress, any powerhead would blow out our seams. Only the water involved in the actual wave, IE the top 3" or so, is what causes stress on the glass.
That being said, a tank is built with glass of a thickness to withstand 24" (or however deep it is). 3" of wave pressure shouldnt make a whole lot of difference. The glass/silicon should never even move.
Acrylic, on the other hand, would be constantly flexing, and unflexing, and I could see that fatiguing the plastic.
Liam
letting it grow
comparing the action created by a wavebox to that of a powerhead is not apples to apples.
If i put my hand down into my tank i feel a decent amount of force lower in the tank that is being created by the wavebox.
If i feel the pressure on my arm then the sides of the tank are feeling it too.
Pressure = stress
RichConley
Attack of the Killer Cute
Liam, if you put your hand on a powerhead, you'll feel pressure too.
The water moving is being replaced by water moving in the opposite direction. Hence, 0 net force. The only place where this isnt true is in the top couple inches.
The water moving is being replaced by water moving in the opposite direction. Hence, 0 net force. The only place where this isnt true is in the top couple inches.
The key to the wave box's motion is it's timing with the frequency of the wave moving back and forth in the tank. If you cycle it just once, no big deal. But after a few cycles and you now have a large part of the body of water moving in step with the wave, so to speak. It's a neat idea but I could see how several years of fluctuating pressure, not on the glass but on the silicone seams, might cause a poorly built tank to begin leaking. I have no idea about GlassCages but without a longterm warranty, I might be a little nervous with the wave box or anything similar.
delta
Impatient Reefer
I have never heard anyone complain about GC's tanks failing, only complaint I have head is that they are not very pleasing to the eye.
Not the same for AGA or Oceanic but the Oceanic were all Bow fronts.
Maybe someone has an experience to share with a GC's tank failing?
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nothing to do with GC but here is all of our fears, regardless of tank manufucturer 
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1069468
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1069468
smcnally
Tankless
Rich, I'm not going to argue with you because I have zero data to prove my point. I will say that I completely disagree with you though, and that I think you are basing your opinion on how you think a wave maker works. Have you ever owned one or sat there for a good while and actually felt the tank rock from one? Comparing it to a power head is absolutely silly. You're comparing something that pushes water in one direction and fights the water volume at all times to something that pushes and pulls water and uses the weight of the water volume to its advantage. If you're going to prove people that use these wrong, at least show some data or experience to back it up. Tunze themselves warn that their wavemaker can shorten the life expectancy of a tank by up to 3 years.
Liam
letting it grow
sorry Rich but i completely dissagree also.
The wavebox drives water low in the tank,the water rises due to the fact that the water comes in contact with the side of the tank,it has nowhere to go but up,this means a force is required to drive the water up and overcome gravity.THERE MUST BE FORCE.Then it heads back the other way leaving a negative behind it,thus inducing more stress.
The sheer fact that your corals are swaying back and forth shows kinetic energy is in effect.
The wavebox drives water low in the tank,the water rises due to the fact that the water comes in contact with the side of the tank,it has nowhere to go but up,this means a force is required to drive the water up and overcome gravity.THERE MUST BE FORCE.Then it heads back the other way leaving a negative behind it,thus inducing more stress.
The sheer fact that your corals are swaying back and forth shows kinetic energy is in effect.
smithcreek
Futurely (*&^#%(@*%
Agreed, isn't that part of the definition of a wave? Have you ever stood in the ocean at a point where the wave isn't cresting, but just about to? The water isn't moving, but there's enough energy in that wave to knock you over.
Gina McReeferson
My sweet Baby David
You are basically jamming and quickly removing ~ a gallon of water into and out of the bottom of your tank in a ripidly cycling manner. The surface of the water is heaving up and down. To raise the water level in your tank like that in such a quick fashion would be producing a surge in pressure in all directions against all the surfaces of your tank, followed by a drop in pressure back to the norm. Even if the pressure change is small, you are talking somewhere on the order of 75-125,000 cycles per day (provided it runs around the clock), this added up over years is bound to have "some" fatiguing effect. How much of an effect I will leave to someone else, I don't feel like digging out the books and spending the next few hours do calculations. 
I imagine the effect is not "huge", esecially when you figure in the fact that our tanks have a rather sizeable "safety factor" built into them, I would be surprised if you did much more than cut into this "safety margin" with actual "damage".
-Dave
I imagine the effect is not "huge", esecially when you figure in the fact that our tanks have a rather sizeable "safety factor" built into them, I would be surprised if you did much more than cut into this "safety margin" with actual "damage".-Dave
NateHanson
Non-member
I don't think there's really much actual disagreement here. We all agree that there's extra force on the tank with a wavebox, and we all agree that water at every depth in the tank is moving.
The debate is more semantic than anything else. Rich and I are just disagreeing with the point that was made earlier that a great deal of weight of water is moving from one side of the tank to the other. That's true, but a nearly equal amount of water is simultaneously slipping past in the opposite direction, offsetting most, BUT NOT ALL, of the force of that water. The difference between the water going one way and the water going the other is that 1" wave at the top.
That's the only net mass that's moving back and forth in the tank.
Now, as far as pressure, I think Dave makes a very good point. I don't know how the numbers would work out (or honestly even how you'd compute "the numbers"
) but if the wavebox created a measureable pressure variation as it sucked and blew, then that would be a source of fatigue as well.
Anyways, my point is that we all agree there's some incremental increase in wear on a tank with a wavebox. And none of us really know what that increase is. Having a wavebox or not having a wavebox isn't going to change that. I doubt Tunze knows either and they've got lots of waveboxes. Personally I wouldn't think it's much, but I think this ultimately is going to come down to a personal comfort level thing.
The debate is more semantic than anything else. Rich and I are just disagreeing with the point that was made earlier that a great deal of weight of water is moving from one side of the tank to the other. That's true, but a nearly equal amount of water is simultaneously slipping past in the opposite direction, offsetting most, BUT NOT ALL, of the force of that water. The difference between the water going one way and the water going the other is that 1" wave at the top.
That's the only net mass that's moving back and forth in the tank.
Now, as far as pressure, I think Dave makes a very good point. I don't know how the numbers would work out (or honestly even how you'd compute "the numbers"
) but if the wavebox created a measureable pressure variation as it sucked and blew, then that would be a source of fatigue as well. Anyways, my point is that we all agree there's some incremental increase in wear on a tank with a wavebox. And none of us really know what that increase is. Having a wavebox or not having a wavebox isn't going to change that. I doubt Tunze knows either and they've got lots of waveboxes
. Personally I wouldn't think it's much, but I think this ultimately is going to come down to a personal comfort level thing.
delta
Impatient Reefer
The force is already there you are just adding to it. The wave doesn't splash off the end of the tank because the is no lateral force created by it.
I don't think the argument that is is only a gal is much of an argument if you do not factor in the velocity of that gal of water. It is not equal to dumping a gal of water at one end of your tank.
I don't think the argument that is is only a gal is much of an argument if you do not factor in the velocity of that gal of water. It is not equal to dumping a gal of water at one end of your tank.
RichConley
Attack of the Killer Cute
Jeremy, it may be more of a stance that if theres a manufacturing defect, its going to break in the first 90 days. If it takes longer than that, chances are it was a setup issue. (tank uneven/stressed/etc)
Its kind of like oceanic's warranty only being valid if the tank is on one of their stands.
RichConley
Attack of the Killer Cute
We're not saying only a gallon. We're saying that only the top couple inches count. IE maybe 10gallons in a 90g size tank.
If all 90g was causing pressure swinging back and forth, the tank wouldnt last 10 minutes. Try it, pad the sides of your tank enough that impact isnt an issue, and then roll a 700lb lead ball around in it.
When the water down below the surface moves, it is being displaced by water moving the other way. Theres no pressure building, or anything like that. The pressure is varying from water height of 18" to 24" (assuming 24" tank, and big wave). None of whats going on below the valley of the wave is creating pressure in any sort of different way than what a powerhead is producing. That wave can be significant amounts of force, but we're talking 10% of the volume, not the whole tank.
