90 Gallon Tank on a 1.2 degree Inclined Floor

[niranjanbt]

Hello,

I recently purchased a 90 gallon cornerflow tank from Marineland and a custom built oak wood stand. The plan is to set up a reef aquarium in my family room.

The ideal spot for this aquarium is a 4ft wide x 2ft deep nook (please check out the attached image). However, I see that the floor is slightly inclined (1 inch over a 4ft span; 1.2 degree to be precise) in this area. I would like to know if this is acceptable or if this is a recipe for disaster.

Thank you all in advance! :thumbsup:

-NT

 

[Sacohen]

You probably would want to shim the stand so the stand and tank are level.
If you don't that right side is going yo have the full weight of the water leaning on it and may give out.
Plus it will just look better.
I can see in the picture that the top of the tank is going down hill compared to the railing .

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[Clowning_Around]

given the conditions you could shim the load areas but if it were me with that much of a difference I would go another route. I would make a new sub base/ plinth / frame that levels the tank/ compensates for the floor issue. I would do so via (4or more) 2x4 cut on edge such that they match the stands bearing members and the perimeter + 1/2 inch width all around (perimeter might have to be dbl members depending on stands makeup for proper bearing) but also cut so that it matches the floors slope profile, then assemble as a frame that is say 2inch on one side and 3+ inch on the opposite. I would then paint it black or match the stands finish if possible then put a handful of screws through the bottom gave into the stands bottom members to keep it in position until loaded. Now you have a level stand, sump and tank.

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[Clowning_Around]

Side note, if you have little ones, or those that visit.... I would consider removing the upper rails and infilling that small wall area to keep from having unwanted things entering the DT or overflow

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[niranjanbt]

Thank you both for the suggestions.

I agree that it would look a lot cleaner with everything leveled up. Especially, me being a person with OCD (I think) :lmao:

I understand that pressure on the right side wall will be slightly higher than that on left due to 1" additional water pressure. However, I am having a hard time understanding how this slight inclination would compromise the structural integrity of the aquarium. Aquariums are generally designed to withstand pressure from water filled all the way to the top edge. How am I worsening the situation by reducing the water level by 1" on one side (left in my case)?

Am I missing anything?

-NT

 

[niranjanbt]

Thank you both for the suggestions.

I agree that it would look a lot cleaner with everything leveled up. Especially, me being a person with OCD (I think) :lmao:

I understand that pressure on the right side wall will be slightly higher than that on left due to 1" additional water pressure. However, I am having a hard time understanding how this slight inclination would compromise the structural integrity of the aquarium. Aquariums are generally designed to withstand pressure from water filled all the way to the top edge. How am I worsening the situation by reducing the water level by 1" on one side (left in my case)?

Am I missing anything?

-NT

 

[GQsmooth]

That looks like a bad location for a tank, it will be a PITA to shim the right side rear since you can't even get in there.

 

[Lsufan]

U definitely want to get it level & u have a few different options of doing so. Another idea that hasn't been mentioned & is the way I would probably go is to figure out exactly what u need & rip a 2 by 4 down & mount it under the stand. So if the floor is straight & just out of level by 1", then rip a 2 by 4 down from 1" to nothing & nail it to the bottom of the stand. That way once u slide the stand into the alcove it is ready to go. That will keep u from having to get to the back of the stand to try & shim it. Even if it doesn't end up exactly right it will make it way easier only having to shim up 1/8" or 1/4" rather then 1"

If u decide just to use shims I would put a 1 by 4 on the lower end on the floor & use shims between that & the stand. U don't want to try to stack multiple shims to get to where u need

 

[Clowning_Around]

U definitely want to get it level & u have a few different options of doing so. Another idea that hasn't been mentioned & is the way I would probably go is to figure out exactly what u need & rip a 2 by 4 down & mount it under the stand. So if the floor is straight & just out of level by 1", then rip a 2 by 4 down from 1" to nothing & nail it to the bottom of the stand. That way once u slide the stand into the alcove it is ready to go. That will keep u from having to get to the back of the stand to try & shim it. Even if it doesn't end up exactly right it will make it way easier only having to shim up 1/8" or 1/4" rather then 1"

If u decide just to use shims I would put a 1 by 4 on the lower end on the floor & use shims between that & the stand. U don't want to try to stack multiple shims to get to where u need

This is basically the same.as.my recommemdation except instead of one side to zero, I proposed a.little height to disguise the unlevel condition a little bit, well as much as you can try to without it turning into a larger project.

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[Linkfalcon]

Why is the house so unlevel where do u live and is this a new or old home is there a sub level below the tank or a concrete slab


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[davocean]

I would take 2x4's and cut them to length of stand, and go from an inch and a quarter to quarter inch to take out that inch if it is consistent, I'd do about 4 of those, maybe more, and a sheet of ply on top, and then I'd hide all that w/ some base trim, but hey, I'm a carpenter, so that's easy for me to do, so depends on your skills.

An inch in 4 feet is a steep drop, but I've seen worse, my last place was an inch and a half in 4 feet, and uneven as it was stone, I actually had to lay down plastic and make a small crete slab to correct that, but you probably don't want to do something like that on that wood floor, and actually my first suggestion would actually help protect that floor and allow it to breath as well as buffer and level.

 

[on the spot]

...I actually had to lay down plastic and make a small crete slab to correct that...

For it's disadvantages this would be the easiest way - make a frame the size of the stand, pour a floor leveling product pad (over plastic sheeting), once cured place the stand on the now level pad, and add a small shoe trim. door stop comes to mind.

 

[Clowning_Around]

For it's disadvantages this would be the easiest way - make a frame the size of the stand, pour a floor leveling product pad (over plastic sheeting), once cured place the stand on the now level pad, and add a small shoe trim. door stop comes to mind.

I would just skip the fill, he only needs a frame under the stands bearing areas for load transfer, the rest doesnt transfer and is just added costs and effort/ i.e. no need for a solid base.

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[der_wille_zur_macht]

Thank you both for the suggestions.

I agree that it would look a lot cleaner with everything leveled up. Especially, me being a person with OCD (I think) :lmao:

I understand that pressure on the right side wall will be slightly higher than that on left due to 1" additional water pressure. However, I am having a hard time understanding how this slight inclination would compromise the structural integrity of the aquarium. Aquariums are generally designed to withstand pressure from water filled all the way to the top edge. How am I worsening the situation by reducing the water level by 1" on one side (left in my case)?

Am I missing anything?

-NT

You're not missing anything. There's no structural risk to the tank whatsoever, it's more of an appearance thing and the potential to interfere with equipment (ie if there's an overflow on the "high" end of the tank, it's just not gonna work).

I don't think an inch in 4' is the end of the world, plenty of ways to shim or compensate. FWIW, my 18" wide nano has nearly an inch of elevation change in the floor underneath it. That's what I get for living in a 200 year old house. I shimmed and it's totally fine. Many many years ago I had a 4' 55g tank in the same spot, no shims. It was fine, too, but it bugged the hell out of me.

 

[ca1ore]

Tank problems arise when there is twisting - that's what pops panels or seams. Being out of level by a full inch across the length of the tank would be unacceptable to me though, and will screw up the overflows.

 

[jayball]

There is no way I would go through the effort of setting up a tank (and a 90 gallon is a fair amount of hours labor to set up) that was going to be an inch out of level. I doubt you want to set up a tank and have the first thing everyone sees is the funky waterline.

 

[Clowning_Around]

You are fooling yourself if you think being out of level doesnt effect the forces by itself. Yes theres some tolerance and forgiveness to an extent, but we are also ( I highly suspect) talking long term application here.

Test this, grab a reusable glad container or one of those shoebox sized sterlite boxes and fill it with water and set it on your kitchen counter. Now observe the side deflection on both ends as well as push it in with your finger to feel the resistance, should be equal on both sides. Now prop up the one side like as if your tank out of level and repeat. You should be able to see and feel the difference, that's the effects of the difference in the pressure being imposed by being out of level. You can continue to exaggerate as needed to notice. Now at what point is to much and at what point in time... I dunno but personally I wouldn't risk it with the potential catastrophic failure, water dmg to the home, loss of the aquarium and livestock. There's already enough to contend with without having one more unnecessary aspect on the back of your mind, is today the day that a side panel busts a seam or blows out a panel.

On top of all that there is the visual aspect which would simply drive me nuts.

I'm guessing simply by the fact that you've made this post that there is a concern and on my opinion rightfully so. I would opt to either adapt the condition as proposed by several above for levelness or better yet fix your home's floor to be level.

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[on the spot]

...this would be the easiest way - make a frame the size of the stand, pour a floor leveling product...

I would just skip the fill, he only needs a frame under the stands bearing areas for load transfer...

I wasn't suggesting first cutting a tapered frame and then pouring a leveling pad. That would be silly. The frame just contains the pour. Perhaps that wasn't clear in my first post.

OP - level it off one way or another. It can be quite annoying seeing and having it seen by all.

Best of luck

 

[der_wille_zur_macht]

You are fooling yourself if you think being out of level doesnt effect the forces by itself. Yes theres some tolerance and forgiveness to an extent, but we are also ( I highly suspect) talking long term application here.

I'm not fooling myself, it's basic physics. The force on the side wall will be, at most, maybe a percent or two different for the angle change we're talking about here. If you don't believe me, we could scratch out a free body diagram I suppose. Most commercial aquariums are built with a safety factor of 5 or larger - changing the distribution of force from the bottom to the sides by a percent or so isn't coming anywhere near even being remotely close to an issue. You've now got a margin of 4.99 instead of 5. Not a big deal.

As Simon mentioned, the real issue when setting up a tank is keeping the supporting surface flat. You need the tank resting on a flat surface, regardless of if that surface is actually level or not. Putting the tank on a flat surface that isn't perfectly level will change the distribution of force in the aquarium by a percent or so. Putting the tank on a surface that isn't perfectly flat (even if it is level!) can change the distribution of force significantly, with the load at the high points going up by several hundred percent. THAT is what breaks an aquarium - being on a surface that's not true. Being unlevel is, by comparison, a complete non-issue.

 

[Clowning_Around]

I'm not fooling myself, it's basic physics. The force on the side wall will be, at most, maybe a percent or two different for the angle change we're talking about here. If you don't believe me, we could scratch out a free body diagram I suppose. Most commercial aquariums are built with a safety factor of 5 or larger - changing the distribution of force from the bottom to the sides by a percent or so isn't coming anywhere near even being remotely close to an issue. You've now got a margin of 4.99 instead of 5. Not a big deal.

I totally agree about the solid engagement of the bearing surface against its respective support. I think we are saying the same one the other subject too, it just comes down to comfort level. I was stating it had some effect, just not none and you stated maybe a percent or so. I also don't have as much faith in the construction and the tolerances Ive seen in some tanks. Sure they may set out to have a builtin safety factor but the actual built factor can be less. We also haven't factored in the additional applied forces of water movement from flow or the forces generated from a large fish while in this application. Also when the dynamics of all of these combined aspects and forces change its not a lateral 1:1 exchange of the increased load in the new application against the intended application with its safety factor. Perhaps its trivial as you suggest, In all honesty, I wasn't wanting to calculate it, so I chose to offer feedback on the side of caution.

Ugggh why'd you have to go and bring up doing free body diagrams

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