Wave Maker Vs. Glass!

[ColBen112]

I have a 90 gallon reef, it is a glass tank. I have always wanted to use a wave maker in my tank and have been skeptical about doing so. I have heard that it will slowly beat your glass until you spring leaks! Does this myth have any truth?

 

[mr_X]

That's completely absurd. You are going to need decent flow in the tank for corals. What are you using for flow currently?

 

[dylan p]

Never heard that b4


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[ColBen112]

I have two 950gph powerheads I want to set them up on a timer to make a wave like motion in the tank but I don't know where I heard it but someone said the repeated hitting of the water on the glass will eventually break your seals

 

[mr_X]

That's not true. I would not alternate the power heads though, since you need them on full time. I suggest getting larger power heads. Two 950s aren't much for a 90 gallon.

 

[Mebbid]

I have two 950gph powerheads I want to set them up on a timer to make a wave like motion in the tank but I don't know where I heard it but someone said the repeated hitting of the water on the glass will eventually break your seals

If that were true... many many many of us would be in deep trouble

 

[Sniperhank]

I can only imagine what would happen if this were true. My vortechs are on one of the pulse modes and would see a similar effect if true.


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[dylan p]

Glass does weaken over Time. So will the silicone. But I don't think a wave maker will affect it enough that you should be worried about it. If the aquarium is extremely old and fragile then it might speed up the process but at that point it shouldn't have water in it anyway


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[myBrainHurts]

If that was true it would take more than a life time to work.

 

[jeffaquarius]

It may or may not be true but you can never underestimate the force of the waves in your tank. The taller and wider your tank is the more stress there is in the glass sealant. That being said, its failure depends on the craftsmanship and the quality of the sealant used.

 

[Swicicki]

I'm going to not pick a little and say how wide your tank is irrelevant. Only tallness matters for pressure


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[jeffaquarius]

If your concern is just the psi at the bottom then yes you are right, but we are talking about the total force exerted in the area of the glass.

 

[Gregcoyote]

Glass can be flexible to a point, but your not developing the forces needed to damage it or the seals. Now even a small shock wave could destroy the tank when full of water, but there is nothing in a fish tank that could create such a wave.

FYI;

Glass includes all materials which are structurally similar to a liquid. However, under ambient temperature they react to the impact of force with elastic deformation and therefore have to be considered as solids.


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[jeffaquarius]

I don't think the OP ever mentioned that it would break the glass. The subject is the seal. Although we know that it is flexible there is a chance that at a certain point it will fail. It may not happen in days or months but in years when the seal flexibility has weakened and becomes brittle. You may think that the waves you see on the water surface is really nothing to worry about. What is really happening in your tank is that the whole volume of water in your tank is like being shaken horizontally back and forth. The oscillation of that small pump may seem very minimal but it is compounding until it reaches enough force to create those waves. If you understand how the laser light works it is somewhat similar to how the force of a small pump is being amplified.

 

[Gregcoyote]

Jeff, my major was lasers. Not sure your analogy holds water (pun intended). But it is a very intelligent way to look at the problem. In the case of a laser, you are pumping the photons and creating a coherent beam. That's not what's happening with a wave maker, even though your analogy of how the pumps work to gain inertia in the wave is accurate.. While the wave does gain some inertia as the water flow moves back and forth, that inertia is not focused in any way. You would splash the water out of the tank before the flows inertia started harming anything I think.

The only thing the pumps do is produce small shock waves thru the water. Even though the effect can be additive if the pumps run alternately, that flow would have to be extremely powerful to place any real force on the seams. Because the velocity of the shock waves are very low, they produce very little energy to the tank walls. They also don't vary the PSI in the tank to any real extent. Now if you had a surge dump bucket style system that hit the tank with 5 gallons a dump, that does vary the pressure on the tank walls and theoretically could weaken the seams after a long period of time. It's about the velocity. Even a small high velocity shock wave could rupture a tank, glass, seals and all. I don't think the OP should worry. His floor will get very wet before he has to worry about seal failure.

JMO.

One other thing, I like using the pumps alternately. X mentioned he thought they should run continuously, I have found the bouncing of the current back and forth helps corals grow better.

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[jeffaquarius]

Now that you mentioned your major is laser then we can talk the same language. If your small circulating pump runs continuously then yes it will not have any effect on the pressure in your tank. You may run the same pump in pulsation but if it's not resonating or synchronizing with the waves then it may still have no effect on the pressure. To create the waves in our tank we have to set the pulsation of that pump so that it resonates to the waves. In laser we amplify the light by reflecting it back and forth by means of mirrors on both ends. In the tank we amplify the waves by reflecting it back and forth to both ends of the tank. I am not talking about a small ripples of water surface in your tank. I am talking about the close to nature waves you create in your tank.

 

[Gregcoyote]

The description of that type of light amplification between two mirrors is accurate, I get what you are referring to. That is as you know called "photon pumping." The mirrors collimate the beam, thus raising its effective energy a lot. But raising photons to a higher energy state is not what's happening between two synchronized pumps. In the case of the pumps, yes you can find a natural frequency between them that increases the waves height, and places a bit more strain on the tank perhaps, but not very much as again, it's not focused. But in no case I can think of other than creating larger more focused and higher velocity shock waves, or dumping a lot of water into the tank all at once (major PSI changes) could you damage the tank. If you built the wave high enough, it would overflow the tank sides. Think about the old example of using a electric fan directed on a sailboats sail. Only works if the fan is not in the sail boat. Interesting exercise though.


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[jeffaquarius]

If we can only measure the swinging of psi on the walls of the tank then may be we can resolve this argument. Just look at this video and can you just make a guess how much force being exerted on the walls when water level goes up and down?

.

 

[Gregcoyote]

That is an extreme example but still indicates my point. The water will start leaving the tank (this one is only about 7/8ths full) before enough force is put on the tank to damage it. You can calculate the PSI delta pretty easily using a calculus equation. The height of the water differential at each end would cause a PSI change for sure, but a minor one. I might in this extreme example be more worried about the waves inertia on the tank ends. If you are generating a standing wave this big, you need to turn your pumps down! Or go surfing.


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[jeffaquarius]

Your example of computing the psi delta is the static pressure of water according to its level. We are dealing with a dynamic pressure which causes the water level to go higher. You are exerting pressure to the water column to raise it up against the wall. It is like dumping of a considerable volume of water into the tank and being repeated over and over. Similar to what you just said.

Now if you had a surge dump bucket style system that hit the tank with 5 gallons a dump, that does vary the pressure on the tank walls and theoretically could weaken the seams after a long period of time. It's about the velocity.

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Again, I am referring to the quality of the sealant and for how long can it withstand when it has already starts to become brittle.