How much rock is too much?

goosey

goosey

New Member
I currently have nearly 100 pounds of live rock in a 50 gallon and will soon upgrade to a 90 gallon (BTW I bought the 48" MH lights so I'm officially committed to the upgrade). I have an overwhelming fear of cracking the bottom of a glass tank. How much is too much weight? Can or should I reinforce the bottom of the tank somehow? I'm afraid of learning the hard way and finding the contents of my tank on the carpet.
 
geoj

geoj

Active Member
Some have use a styrofoam or polystyrene pad between the tank and stand. Adding strength and support, keeping the glass from bending.
 
small triggers

small triggers

Active Member
Yeah the pad under the tank is a good idea, also use eggcrate on the bottom of your tank and then put the rock ontop of that with your sand after like normal,,, it will keep the rock from resting on the bottom and possibly causing a crack,,, i have really only heard of it once,,,, but once is enough right? (i have an acrylic tank so i dont worry TOO much)
 
spanko

spanko

Active Member
This is a good question. How about those that have large tanks with stands that support the tank only around the outside frame? Is tempered glass on the bottom of these tanks strong enough to hold possibly hundreds of pounds of rock?
 
E

eric b 125

Guest
a have a 125 with the kind of stand that spanko is talking about. tempered glass is pretty tough. its strong enough to hold roughly 1000 lbs of water. the eggcrate is a good idea, i feel, because its rigidity helps disperse the pressure points of the LR on the bottom pane. it also gives the rock something to grab onto when doing the aquascape. tanks are built with this stuff in mind.
 
nysharkbait

nysharkbait

Member
I've always heard you want equal to double the gallons of water in pounds of rock. That being said, I have to believe this rule basically says tanks can take it.
 
flower

flower

Well-Known Member

I Have a 90g with about 75 to 80 pounds of rock...I had the same rock in the 55g and 75g. I added a little bit more but not much, I also have two large cave which takes up space...I think the tanks can handle the weight..But leave some room for fishy to swim..Too much rock just doesn’t look good. JMO
 
spanko

spanko

Active Member
So I am thinking it better to have a stand with a full bottom on it. Then you can put a rubber pad or thin pc. of styrofoam under the tank to support the glass.
Anyone elses thoughts on this?
 
xcali1985

xcali1985

Active Member
You should be able to fill the tank up with 100% sand and not crack the glass. It will be heavy as all hell but should be sound.
 
florida joe

florida joe

Well-Known Member
structural integrity is not the only thing to consider when wondering of you have to much rock. Remember rock displaces water and all things considered water volume is one of our greatest allies
 
drtito

drtito

Member
old tanks do not have the bracing that new tanks have. top or bottem
My old tank cracked from the bottem too much wight,rocks on the glass,bad stand ,or no bottem brace, who knows but at 5 am i was filling buckets.
Now i have egg creat, in the tank and a pad sandwiched between plywood under it. I feel safe. I did call A.G.A. and was told the 125 could handel a full rock wall along the back and ONE side no problem.
hope that helps. good luck
 
goosey

goosey

New Member
You guys are great! Thanks for the ideas. I might rethink the stand I was going to use to allow support underneath. Thanks!
 
flower

flower

Well-Known Member
Originally Posted by DrTITO
http:///forum/post/3175665
old tanks do not have the bracing that new tanks have. top or bottem
My old tank cracked from the bottem too much wight,rocks on the glass,bad stand ,or no bottem brace, who knows but at 5 am i was filling buckets.
Now i have egg creat, in the tank and a pad sandwiched between plywood under it. I feel safe. I did call A.G.A. and was told the 125 could handel a full rock wall along the back and ONE side no problem.
hope that helps. good luck


I doubt the weight broke the tank, most likely you cracked it dropping a rock or when one fell and you didn’t notice..Then over time it lost integrity.
Stuff made years ago is made 100% stronger than the cheap stuff they make today. Medicine has improved, but cars, fish tanks, houses and household stuff are made as cheap as possible.
Years ago they tried to make stuff that would last a hundred years. Then manufacturers found out they can make more money if they make it cheap, sell it for more, and if it doesn't last you have to replace it sooner.
Try lifting an all glass 10g aquarium made 20 years ago..that’s right they are indeed still around, and one made yesterday. The weight difference is amazing. Acrylic fish tanks IMO has to be one of the greatest rip offs they have come up with, the stuff scratches so much you have to replace it in 5 years even if you are carful.
 
firefightremtp

firefightremtp

Member
i know I am new, but, with my firefighting experience I know a thing or two about water. Water weighs just over 8.3 lbs/gallon. So if you take a relatively common 150+ gallon tank, you are talking about close to 1000 lbs just of water weight. The glass has to be made to be able to handle that type of weight. just my .02 cents....
~grace
 
E

eric b 125

Guest
a 150, water alone, would weigh close to 1200 lbs. plus, saltwater weighs a little more than fresh. i think with the amount of salt we dissolve/ gal, the weight comes out close to 8.556 lbs/ gal. not a huge increase, but an increase nonetheless.
 
firefightremtp

firefightremtp

Member
Originally Posted by Eric B 125
http:///forum/post/3175984
a 150, water alone, would weigh close to 1200 lbs. plus, saltwater weighs a little more than fresh. i think with the amount of salt we dissolve/ gal, the weight comes out close to 8.556 lbs/ gal. not a huge increase, but an increase nonetheless.
wow, thats interesting. It makes sense though...
 
rigdon87

rigdon87

Member
Originally Posted by Eric B 125
http:///forum/post/3175331
a have a 125 with the kind of stand that spanko is talking about. tempered glass is pretty tough. its strong enough to hold roughly 1000 lbs of water. the eggcrate is a good idea, i feel, because its rigidity helps disperse the pressure points of the LR on the bottom pane. it also gives the rock something to grab onto when doing the aquascape. tanks are built with this stuff in mind.
+1.I have the standard aga stand(what eric and spanko are talking about) and i have 300+lbs of lr in my dt and about 150lbs of ls.You gotta think on these larger tanks the glass is 1/2'-3/4's thick.The weight of rock, sand and water alone will not have any negative affects on the tank,IMO you should worry about the structural integraty of the stand before the tank as it would probbly buckle long before the tank.
Just a thought....
 
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