How much LR per gallon of tank? OR

[olsenshouse]

is there a weight limit a tank can hold? I have a 55 gallon tank and I have 1 rock that is 50+lbs and a couple more that are around 15lbs. So all in all, I have around 65-70lbs of live rock in my tank already. Can I add more? or will it be too heavy for the tank to hold and will crack it? Any input would be appreciate. Everyone is so knowledgeable here!

 

[jrgilles]

huh, interesting questions. You're around 1.2 lbs/gallon. Numbers I've heard on target lbs/gallon are 0.75-1 in DT and 1.5 in sump. So, I'd assume it could hold at least 1.5 lbs/g. It displaces water weight, but I'm curious now. I'll tag along

 

[olsenshouse]

Thanks jrgilles. I've heard a pound per gallon but I'd like more.

 

[mfinn]

You have one single rock that is 50+ lbs?
That's a pretty big chunk of live rock.
Any pics?

 

[olsenshouse]

Once the new iphone comes in I will take a pic. The thing is huge. Got it from mopar reefer.

 

[johnpeezy]

there are tricks to help dispurse the weight of the rock throughout the bottom of your tank more evenly like lining the bottom of the tank with eggcrate before setting it up and placing some foam padding between the tank and the stand as well.

but the still dosn't answer the question......

 

[olsenshouse]

Found this on Simplified Reefkeeping (www.simplifiedreefkeeping.com)

How much "Live Rock" is required?

It is very important to have the correct amount of live rock. Some people have gotten carried away with the idea that if some is good, more must be better. This is not true! As with all concepts of reef keeping, balance is very important here. If you don’t have enough live rock, natural internal filtration will be ineffective, because the bacterial colony on the rock will be inadequate to perform the task. Or, if you have too much live rock, you will have dead spots on it. These are areas of live rock that are covered with other rock, blocking some surfaces from light and water circulation. These dead spots are likely to trap waste, sediment, uneaten food, and many other products you would otherwise remove regularly. When waste products accumulate in these areas, they will be a sure food source for micro-algae, which will thrive, causing diminished water quality.

This is referred to as “stacking” the rock, and it should be avoided at all costs.

The correct amount of live rock to have in a reef tank is between a minimum of 1 pound per gallon and a maximum of 1.75 pounds per gallon. Somewhere in the middle, like 1.35 pounds per gallon, would be ideal. Do not exceed 1.75, unless you want to turn some quality live rock into base rock, which would take at least a year to recover and resemble what it was before other rock was stacked on top of it.

I have met many people who have jammed as much live rock into their tanks as would physically fit, in an effort to create a natural system. The only result they got was a natural disaster. Two-thirds of the rock died. The water had so much nutrient in it that it could not be reused. They had to start all over again, rinsing all the rock, buying another tank to use the excess rock, or trying to sell the rock back to the store (as base rock). They learned that when it comes to amounts of live rock, more is definitely not better. Again, do not exceed 1.75 pounds per gallon.

Amounts and quality of live rock for a 55-gallon setup: (55 gallons x 1.5 = 82.5 lbs.)

 

[dogfrog]

I also have a single rock over 50 lbs and 2 around 30 eack in a glass tank.

Most of my rock is sitting about 2 1/2" off the bottom on a platform made of pvc pipe and egg crate. The tank in sitting on foam board

In total I have about 150 lbs of rock and around 350lbs of sand. And no I am not worried it’s to much weight for the tank. I was more worried that a rock could fall and crack the glass.

 

[olsenshouse]

How big is your tank dog?

 

[ac7av]

That really just doesn’t make any sense but I can see how it sounds good on paper. That’s all fine if you’re talking about putting in all live top layer rock into a new system. I think most people do not waist there time or money doing that. I use three levels of rock. Base rock that is mostly solid and not very pours, a layer of extremely open pours rock and then the top layer rock what is mostly medium pours rock. I’m sure I have more then 2lb per gallon in my tank and I can assure you that there was not dye off because it was all dead to start with. The way the rock is stacked is just as important as how much you have. A 50lb rock is just not going to do much compared to similar constructed rock of 5lb each creating a 50lb stack. Way more surface area in the smaller boulders. Quality live rock means nothing, base rock is still alive. You’re making it seem like the rock on the bottom it dead and that’s just not the case. That is where most of your denitrifying bacteria is doing its job. The lower flow and lower oxygen environment is required for this to happen, it’s not a bad thing. Just my opinion on the subject. But if one was to do like you say and jam as much as they can of ultra premium live rock in to a tank and it crashes then they got what was coming to them by basically by over stocking a tank that wasn’t ready or cycled. It wasn’t the quantity of rock in the tank that did it, it was the bio load that did it in.

 

[dogfrog]

Its a 220

 

[lvsuckerfish]

i have been told 1 -2 lbs a gallon 2 being better 1 being ok..... hobbist started to trend to open tanks as to where more rock has been seen in the sump/ fuge area. you can have more live rock in the display but you will deal with dead spots and ditrius build up in those dead spots. I think i am at a little over 1 lbs ber gallon in my 240 with lots of rubble in my sump....

Weight wise as much as the glass will hold as the water will displace the weight some also.

 

[bigblue141]

A good rule of thumb is just to make sure that you have good water flow over all your rocks.

Don't expect premium rocks to stay that way if you put them in the on the bottom of your tank and shade them with other rock.

The article you posted has some good points to it, but how are you supposed to make caves and caverns if you do not stack your rock. I stack my rock and have very large openings for my critters to dart in and out of. My shrimp like hanging out upside down on the tops of the caves. The open areas in between the rocks create an area for water to regularly flow through. I also have hundreds of snails and hermits to help keep everything clean.

The largest rock in my system is about 10 - 12lbs. I'm tempted to chisel some of it off so it can be it's own free standing tunnel, and it will allow more water flow.

I think the author of the article you posted was just referring to you do not want to stack your rock on top of it self to make a solid rock pile where you cannot get water to flow through it. With no water flow you can get the dead spots the author was referring to.

Just my 2 cents, and hope I didn't ramble on too much...

 

[ac7av]

A good rule of thumb is just to make sure that you have good water flow over all your rocks.

Don't expect premium rocks to stay that way if you put them in the on the bottom of your tank and shade them with other rock.

The article you posted has some good points to it, but how are you supposed to make caves and caverns if you do not stack your rock. I stack my rock and have very large openings for my critters to dart in and out of. My shrimp like hanging out upside down on the tops of the caves. The open areas in between the rocks create an area for water to regularly flow through. I also have hundreds of snails and hermits to help keep everything clean.

The largest rock in my system is about 10 - 12lbs. I'm tempted to chisel some of it off so it can be it's own free standing tunnel, and it will allow more water flow.

I think the author of the article you posted was just referring to you do not want to stack your rock on top of it self to make a solid rock pile where you cannot get water to flow through it. With no water flow you can get the dead spots the author was referring to.

Just my 2 cents, and hope I didn't ramble on too much...

Exactly!! Couldn’t have said it better.
How can you have rock work for fish to hid in like many need if you don’t stack to create these spaces.

 

[reefbobc]

I agree and think you guys are right on concerning this!

 

[Scooterman]

I've had tanks with "0" rocks, misconception if you think it necessary to have LR at all. Fact is you could improperly over crowd your tank as mentioned & make some of it useless or build up so much detritus you have nitrate problems etc. The amount of rock as in 1 or 2 pounds became a common practice to make things easier for the beginner. Depending on your equipment, bio-load & desired looks all play in part of how much LR you should or may want or need. The Idea is to use it to help keep your system stabilized, easier to keep difficult fish & corals & to know that comes with experience, learning from truly qualified people, (which IMO too many people think they are that qualified) LOL!
If I was to make one recommendation, find real articles as in advanced aquarist. To answer the original question, the biggest damage IMO is dropping or having a rock fall on the glass, that said most bottoms are tempered to add strength in supporting extra weight.

http://www.reeffrontiers.com/forums/showthread.php?t=26533

 

[ac7av]

I don’t believe anyone was saying that rock is necessary at all. It is just one of those things like a protein skimmer or circulation pump or even lights. None of them are necessary. I too have run tanks with out any one of these things. It all comes down to what you want to accomplish in your tank and what kind of maintenance you are willing to put into it

 

[olsenshouse]

You have one single rock that is 50+ lbs?
That's a pretty big chunk of live rock.
Any pics?

Here is a pic of the big rock.

 

[fayzane]

I was told 1lb live rock per gallon as a rule of thumb. BUT, not all LR is created equal. Rock that is exceptionally porous (and good for filtration) will be much lighter than a similar sized rock that is much denser. Also, you can use 'base rock' for your foundation and put some LR in there and all of it will become LR over time.

Just try to select rock as porous as possible, and try to arrange it for ease of maintainence and attempt to avoid creating any 'dead' spaces.

 

[OldFishMan]

I was told 1lb live rock per gallon as a rule of thumb. BUT, not all LR is created equal. Rock that is exceptionally porous (and good for filtration) will be much lighter than a similar sized rock that is much denser. Also, you can use 'base rock' for your foundation and put some LR in there and all of it will become LR over time.

Just try to select rock as porous as possible, and try to arrange it for ease of maintainence and attempt to avoid creating any 'dead' spaces.

This is true --- live rock should come with a load of live things on it and living in it. It needs to be porous for the denitrifying bacteria to colonize the low oxygen areas like small holes, etc,. It would take a lot of good rock by itself to denitrify the water on it own. Also, you will be displacing a lot of water and with less water in the system the Nitrates rise faster. Live rock is only one small piece of the puzzle.

Enjoy

OFM