# How many Rocks/Weight can an aquarium hold?



## zjafry

I have recently picked up a lot of rocks, around 170 pounds worth of it. I am a little concerned that the tank won't be able to support the weight of the rocks. 

A little background. I will be splitting the rocks between a 75 gallon and a 120 gallon tank (making it approximately 100 pounds of rock for each tank, roughly). The rocks would be sitting on sand. Some of the individual rocks can weigh between 20-30 pounds. 

Do you think I have a reason to worry? I'm considering getting plastic egg crates to help dissipate the weight of the rocks. Any thoughts, considerations, input or personal experience would be greatly appreciated. 

Thank you.


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## Gypsy

My gut reaction is that is a lot of weight for a single tank. My practical suggestion is smaller rocks. Nothing is more difficult than struggling to lift / move a heavy rock in an aquarium when looking for a dead / hiding fish... 

But I am no expert.


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## cichlidsnorth

That wieght I would think to be fine in those tanks. I have tanks with that much rock in them with no propblems. The only problem I see is what is already stated about lifting heavy rocks into a tank without damaging the tank or dropping the rock in the tank, care must be taken.
And again this is only MY experience, I make no garranties on this not damaging your tank, but I put that much rock in mine with no problems


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## Aquatic Designs

I have 750 lbs of texas holey rock in my 220. I also have 1/2' pvc DIY undergravel circulating pipe under the load. It also rests on 3/4" glass. 

The pvc is arranged in an s pattern with tight 90 to 90 turns. This way the pvc is about 2-3" apart and is supporting the rocks and allows for an uneven supported load to distribute evenly over more surface area of the bottom. And it doesn't point load. I cut slits in it and put a cap on one end, powerhead on the other and I circulate the underneath of my rocks so there is no dead spaces. 

Or you can use light diffuser. Where the name egg crate came from I have no idea but it's been used forever. Which if you needed some I have a full sheet of it you can have.


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## zjafry

Thanks for the help!

I ended up buying some plastic egg crates that I'll use... just to be safe. 

Thanks again


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## Windowlicka

Not very scientific, but still, demonstrates that the tempered glass base in the average aquarium can hold more weight than we might otherwise care to imagine/realise...!


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## shaguars7

I would say that there is not really too much of a limit when it comes to rocks as long as the tank bottom has been prepared. I have around 100lbs ina 75 and probably 200 in a 135. I just put egg crate in the bottom footprint of the tank and stacked them on it....I have had no problems for years so i would not be too concerned imo.


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## carmenh

So how does one know if their tank is tempered glass? Cuz I have a lot of LR in both my 90g tanks (right on the glass bottom, as I was advised when I set up the first one) and I never worried about it until I started reading this thread!



Windowlicka said:


> Not very scientific, but still, demonstrates that the tempered glass base in the average aquarium can hold more weight than we might otherwise care to imagine/realise...!


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## AquariAM

carmenh said:


> So how does one know if their tank is tempered glass? Cuz I have a lot of LR in both my 90g tanks (right on the glass bottom, as I was advised when I set up the first one) and I never worried about it until I started reading this thread!


The right on the glass bottom is more of an anti topple thing than a weight distribution thing. If you've been ok for a long time there's no reason you won't continue to be. Glass can take a lot of sustained pressure. It just can't take rapid changes in pressure.

Ie, if you gently placed a 100lb load on a sheet of glass, no problem. DROP that 100lb load, smash.


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## carmenh

LOL, hopefully! I hate to think of the repercussions if one of them broke! I'm already banned by the hubby from having anything over 100g after an unfortunate leak incident with my old 125g...one more and I'll be down to a 10 gallon maximum! 



AquariAM said:


> The right on the glass bottom is more of an anti topple thing than a weight distribution thing. If you've been ok for a long time there's no reason you won't continue to be. Glass can take a lot of sustained pressure. It just can't take rapid changes in pressure.
> 
> Ie, if you gently placed a 100lb load on a sheet of glass, no problem. DROP that 100lb load, smash.


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## AquaNeko

Hmmm... while it's not a rocks that broke this aquarium.


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## carmenh

LOL I remember seeing that! What a knob!


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## AquariAM

AquaNeko said:


> Hmmm... while it's not a rocks that broke this aquarium.


Not even Mama can save him .


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## AquaNeko

AquariAM said:


> Not even Mama can save him .


That was such a magic putty or whateer Billy Mays was pitching before (RIP Billy  ) golden test senario right there if it worked that is.

IIRC that video with the rocks is ~250lbs concentrated on the bottom on the tank right?


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