Jestersix

Just found sand in the seal of my RSR250...

JVU said:
When you do have more time, and if you want to, I think all of us would appreciate learning more about the theory and practice of how you approach this. Pretty much all of us have to do this and few if any of us have your level of experience. I would suggest making a separate thread so it isn’t buried here. Make it as detailed as you want, we love to geek out on details. If you make it really detailed and intimidating, it might even drive more business to your install crew :)
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Will do!
 
IOnceWasLegend said:
Seconding this. I tried to be as careful as possible when leveling the tank before I installed it, but also recognize there may be 'unknown unknowns'. As I move into larger tanks this would be EXTREMELY helpful, and thank you!
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Yeah. Use tanks is a dice rolls so I am sure leveling may/may not be the only reason.

Tank that had been sitting around for too long with residual salt can compromise the seams too. As the water evaporates, the remaining salt crystal can dig themselves into the weakest part of the seams. One of the old tanks I had in the shop did this recently, actually. It was holding water just fine until the new owner set it up few months later and it sprung a leak where the salt creeps had dug right through the silicone.

Additionally, the structural integrity of your stand could’ve also been a culprit. If there are any sign of water damage anywhere on the stand, then I am sure there also somewhere else you don’t see. These unseen deformities can cause uneven pressure spots that will eventually lend itself to seams failures. Remember, glass is extremely ridgid so pressure amplification on the bottom pane is very serious issue. When I spec’ed out flatness on the top of a welded stand, it has to be less than 1mm since I never use leveling mat. Tank just goes straight on top of plywood with just a 1/4 Starboard foam core.

How you transported the tank also could be the reason. Have you notice how a brand new tank is supported during transports? They are typically fully brace on all sides or corners. The bottom support is especially critical because the tank needs to be on a super flat surface. However, with used tanks, most people just throw the thing in the back of their vehicles with a blanket and some straps while the tank free to jostle around. So, just put that into perspective for a second and imagine the stress you put on those poor seams…on a rimless tank.

As you can see, a lot can go wrong.
 
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I am not sure I agree coming from someone who started out life as a structural engineer. Flatness and uniform support would be way more important than level especially given the material property differences between glass, silicone and stands.

If your tank is out of level yet still uniformly supported, you really just have a lille more vertical water pressure on 1 or 2 side panes than the other 2, and the tank should be designed to hold water to the absolute RIM of the tank with no issue. Adding 1" water head should be well within the safety factor of any design. If you are flat and just slightly out of level all the forces are still "normal" and you would not have any odd internal stresses that would be outside what the tank should be designed for. We use the same formulas to design concrete formwork and retaining structures that one would use to design a fish tank, just using different material properties and my junior engineers can do this with no problem.

If you were out of FLAT, you can create all kinds of internal stress points in the glass and additional loading in the joints that could exceed design assumptions. These stresses can get incredibly complicated to calculate taking your simple calculations for a box holding water, which you could calculate with basic understanding of "Statics" or a first year structural engineering course, to understanding Stresses and Structural Dynamics (which will take you through the next 2 years of school) and requires you to know differential equations, material properties, etc, now often done with computer modeling due to the complexity. Stresses get difficult to explain quickly as they are often unintuitive and are often very difficult to spot. There are also no easy Rules of Thumb people could count on besides make your base flat and RIGID, and of corse level to reduce them. A uniformly supported load is much more important than a slightly out of level load. You intuitively know this when you are trying to crush something like a soda can. You can push up down left right all you want, but twist it or apply a pin point load and it fails. Go get 2 cheap aqueon tanks and fill them with water. Put one on a rigid structure and the other on the ground. Now, lift both tanks with a jack/lever by the corner. Which do you think will fail first. The one lifted on the platform or the one lifted by the tank corner itself?

Re: Rimless Tanks - As long as the glass is thick enough, your base is flat plus you are not hanging lights and a bunch of junk on the top (which apply unintended stresses) these are fine. (also assuming you are comparing them to an equally engineered rimmed/braced tank which would have thinner glass, etc). Rimless tanks with a bunch of light brackets clipped on the back freaks me out, especially the big ones. You do need to be more careful with them especially moving them around though because of uneven loading and a lack of top bracing. Setting them on their side is a bad idea for example.
 
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Qwiv said:
I am not sure I agree coming from someone who started out life as a structural engineer. Flatness and uniform support would be way more important than level especially given the material property differences between glass, silicone and stands.

If your tank is out of level yet still uniformly supported, you really just have a lille more vertical water pressure on 1 or 2 side panes than the other 2, and the tank should be designed to hold water to the absolute RIM of the tank with no issue. Adding 1" water head should be well within the safety factor of any design. If you are flat and just slightly out of level all the forces are still "normal" and you would not have any odd internal stresses that would be outside what the tank should be designed for. We use the same formulas to design concrete formwork and retaining structures that one would use to design a fish tank, just using different material properties and my junior engineers can do this with no problem.

If you were out of FLAT, you can create all kinds of internal stress points in the glass and additional loading in the joints that could exceed design assumptions. These stresses can get incredibly complicated to calculate taking your simple calculations for a box holding water, which you could calculate with basic understanding of "Statics" or a first year structural engineering course, to understanding Stresses and Structural Dynamics (which will take you through the next 2 years of school) and requires you to know differential equations, material properties, etc, now often done with computer modeling due to the complexity. Stresses get difficult to explain quickly as they are often unintuitive and are often very difficult to spot. There are also no easy Rules of Thumb people could count on besides make your base flat and RIGID, and of corse level to reduce them. A uniformly supported load is much more important than a slightly out of level load. You intuitively know this when you are trying to crush something like a soda can. You can push up down left right all you want, but twist it or apply a pin point load and it fails. Go get 2 cheap aqueon tanks and fill them with water. Put one on a rigid structure and the other on the ground. Now, lift both tanks with a jack/lever by the corner. Which do you think will fail first. The one lifted on the platform or the one lifted by the tank corner itself?

Re: Rimless Tanks - As long as the glass is thick enough, your base is flat plus you are not hanging lights and a bunch of junk on the top (which apply unintended stresses) these are fine. (also assuming you are comparing them to an equally engineered rimmed/braced tank which would have thinner glass, etc). Rimless tanks with a bunch of light brackets clipped on the back freaks me out, especially the big ones. You do need to be more careful with them especially moving them around though because of uneven loading and a lack of top bracing. Setting them on their side is a bad idea for example.
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This is what I’ve been told before in regards to flat vs. level.
To clarify, you are saying setting a rimless tank on its back for moving it would be bad compared to on its bottom?
I’ve had to do that for Red Sea tanks before because of the bulkheads can’t be removed so it can’t sit on The bottom easily. Guess I should use a board with a cutout for the bulkheads For it to sit on instead of putting on its back?
 
You just need to be more careful when applying other loads to it or storing long term. Like, it if you had it in a car and you hit a big bump, ideally the tank would not be on its side. You would not store your glassware on it side either for the same reason. The rim is fragile, just like a cup.
 
Qwiv said:
I am not sure I agree coming from someone who started out life as a structural engineer. Flatness and uniform support would be way more important than level especially given the material property differences between glass, silicone and stands.

If your tank is out of level yet still uniformly supported, you really just have a lille more vertical water pressure on 1 or 2 side panes than the other 2, and the tank should be designed to hold water to the absolute RIM of the tank with no issue. Adding 1" water head should be well within the safety factor of any design. If you are flat and just slightly out of level all the forces are still "normal" and you would not have any odd internal stresses that would be outside what the tank should be designed for. We use the same formulas to design concrete formwork and retaining structures that one would use to design a fish tank, just using different material properties and my junior engineers can do this with no problem.

If you were out of FLAT, you can create all kinds of internal stress points in the glass and additional loading in the joints that could exceed design assumptions. These stresses can get incredibly complicated to calculate taking your simple calculations for a box holding water, which you could calculate with basic understanding of "Statics" or a first year structural engineering course, to understanding Stresses and Structural Dynamics (which will take you through the next 2 years of school) and requires you to know differential equations, material properties, etc, now often done with computer modeling due to the complexity. Stresses get difficult to explain quickly as they are often unintuitive and are often very difficult to spot. There are also no easy Rules of Thumb people could count on besides make your base flat and RIGID, and of corse level to reduce them. A uniformly supported load is much more important than a slightly out of level load. You intuitively know this when you are trying to crush something like a soda can. You can push up down left right all you want, but twist it or apply a pin point load and it fails. Go get 2 cheap aqueon tanks and fill them with water. Put one on a rigid structure and the other on the ground. Now, lift both tanks with a jack/lever by the corner. Which do you think will fail first. The one lifted on the platform or the one lifted by the tank corner itself?

Re: Rimless Tanks - As long as the glass is thick enough, your base is flat plus you are not hanging lights and a bunch of junk on the top (which apply unintended stresses) these are fine. (also assuming you are comparing them to an equally engineered rimmed/braced tank which would have thinner glass, etc). Rimless tanks with a bunch of light brackets clipped on the back freaks me out, especially the big ones. You do need to be more careful with them especially moving them around though because of uneven loading and a lack of top bracing. Setting them on their side is a bad idea for example.
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In all my installations…flatness, uniform load supports, AND leveling are all equally important. While I believe in the math completely, I can’t trust workmanship with the same conviction so those three factors must be perfect.

Oh and thank you! for speaking my language! other than a possible disagreement on the importance of leveling, I am glad we’re in complete agreement with the other points.
 
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robert4025 said:
In all my installations…flatness, uniform load supports, AND leveling are all equally important. While I believe in the math completely, I can’t trust workmanship with the same conviction so those three factors must be perfect.

Oh and thank you! for speaking my language! other than a possible disagreement on the importance of leveling, I am glad we’re in complete agreement with the other points.
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Pretty sure most tanks are designed with seat of the pants gut feeling engineering and craftsmanship where your volume of installs is likely worth more than all my engineering books combined.
 
The issue with level is that a lot of the floors in the bay are not level. Do you want your stand to be square, or have your tank be level? High quality craftsmanship can get you to either one depending on if the stand is built on or off site. I tend to agree with the sentiment that flatness is the most important driver here to reduce local stress on the glass and seams.

Transport throws another huge wrench in the equation. As Rob noted, the packaging of an aquarium is designed with transport in mind. Our cars are not flat and padded like the crates, so seams see huge stresses during car transport relative to normal use.
 
H2OPlayar said:
The issue with level is that a lot of the floors in the bay are not level. Do you want your stand to be square, or have your tank be level? High quality craftsmanship can get you to either one depending on if the stand is built on or off site. I tend to agree with the sentiment that flatness is the most important driver here to reduce local stress on the glass and seams.

Transport throws another huge wrench in the equation. As Rob noted, the packaging of an aquarium is designed with transport in mind. Our cars are not flat and padded like the crates, so seams see huge stresses during car transport relative to normal use.
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Question. I know some floors may be both not flat and not level. Is there a way to mitigate that without actually tearing up the floor (e.g. using a plywood/solid flat base overlaid on top of the floor)?
 
IOnceWasLegend said:
Question. I know some floors may be both not flat and not level. Is there a way to mitigate that without actually tearing up the floor (e.g. using a plywood/solid flat base overlaid on top of the floor)?
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Yes, I have a personal vendetta against tanks that I have to bend over to look at, so I was looking at systems and thinking of building a stand for the stand.

A piece of high quality marine grade plywood underneath the stand is not a bad idea, but it isn't just the floor, the entire house is likely not square relative to plum, so shims may be needed under the plywood to support it completely.
 
All of my tanks have come unlevel since I installed them with those plastic brown shims under the stands. They stayed level about the first year but now water lines are visually unlevel. One is a RSR, other 2 are custom tanks with aluminum stands which sit on concrete in my garage, which came unlevel in the same direction indicating something underneath the stands moved. My guess is the ground underneath my house literally shrinks or swells depending on the season. So in my case I feel leveling is totally out of my control, but luckily have not had any leak issues. I wonder if anyone else has other hypotheses they could suggest.
 
Chromis said:
All of my tanks have come unlevel since I installed them with those plastic brown shims under the stands. They stayed level about the first year but now water lines are visually unlevel. One is a RSR, other 2 are custom tanks with aluminum stands which sit on concrete in my garage, which came unlevel in the same direction indicating something underneath the stands moved. My guess is the ground underneath my house literally shrinks or swells depending on the season. So in my case I feel leveling is totally out of my control, but luckily have not had any leak issues. I wonder if anyone else has other hypotheses they could suggest.
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You’re gambling!
 
Qwiv said:
Stand should be Square, Flat and Rigid. Level stand with Shims. My tank is on a hump in my floor, so I just have it shimmed all the way around so that it is level.
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That’s what I do with all my tanks also. If there’s a hump on the floor, the system must be shimmed high enough to clear it to avoid stand deformity over time.
 
You can measure the corners of the stand to make sure they are the same length and square, that would eliminate stand moving concern. Does you tank go in and out of level, or is if just creeping out of level constantly one direction? Leveling a tank can be done, but I would only worry about it if it was moving unevenly or really bad. Concrete is pretty good at telling you you have uneven settlement with cracks.

The ground most certainly moves depending on what the dirt is composed of. Not a Soil or Civil engineer, so I only know the basics, but clay soils will shrink/expand with moisture, silty dirt will slowly wash away causing settlement and many more combinations than you could even imagine. My house moves over the year from water in the dirt.
 
Qwiv said:
You can measure the corners of the stand to make sure they are the same length and square, that would eliminate stand moving concern. Does you tank go in and out of level, or is if just creeping out of level constantly one direction? Leveling a tank can be done, but I would only worry about it if it was moving unevenly or really bad. Concrete is pretty good at telling you you have uneven settlement with cracks.

The ground most certainly moves depending on what the dirt is composed of. Not a Soil or Civil engineer, so I only know the basics, but clay soils will shrink/expand with moisture, silty dirt will slowly wash away causing settlement and many more combinations than you could even imagine. My house moves over the year from water in the dirt.
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We have a super clay-ey soil. I will keep an eye on whether the tanks move back by the end of the summer when things get really dry again :)
 
Chromis said:
We have a super clay-ey soil. I will keep an eye on whether the tanks move back by the end of the summer when things get really dry again :)
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Just +1ing houses can move seasonally. My area is extremely clay filled soil. During different seasons doors close better or worse because the house moves. We had to expand door bolt holes because the deadbolts couldn't be shut during the winter. We have neighbors who have separate summer and winter locks, and only one can close at a time depending on how much rain is in the soil.

I never experienced such a thing in the Midwest, even with old houses, so I'm not sure if it's a CA soil thing or an artifact of the water cycle.

I have no expertise on any of this, but I too find it not clear why leveling would be a huge deal in a static setup. Unless there's a potential torque involved because the water force is no longer at a right angle, but is on an angle.

However with all that, it feels like sloshing around from wave makers or gyres would be causing more variable forces than a bit of out of level, and I've never heard someone say those are dangerous.
 
Ok y’all, crazy idea but, should we invite someone to give a guest talk on this topic? I found for example this Solidworks talk which included an aquarium force model by Alon Finkelstein. If he is willing to expand his model to the various unlevel-flat, unlevel-uneven, etc rimless aquarium scenarios, maybe we could get some questions answered by CAD simulations.

@IOnceWasLegend check out where the hotspot is in this screenshot from the presentation of forces on the glass!

2472A4E7-8E9B-455C-8ADF-84402557AC46.png
 
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