rock?
- Thread starter doadster
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MotherFish
New member
That depends on how dense the rock is.
The denser the rock, the less water will be displaced.
The density of seawater is about 64lbs per cubic foot, or about 8.5lbs per gallon.
If your rock was the same density of the water, neutrally buoyant (neither sinks nor floats), it would displace about 11.76 gallons of seawater.
Assuming your rock is denser than the water, negatively buoyant, it will displace much less than that, maybe even half that amount.
The only way to know how much your particular rock will displace is to dunk it and measure.
The denser the rock, the less water will be displaced.
The density of seawater is about 64lbs per cubic foot, or about 8.5lbs per gallon.
If your rock was the same density of the water, neutrally buoyant (neither sinks nor floats), it would displace about 11.76 gallons of seawater.
Assuming your rock is denser than the water, negatively buoyant, it will displace much less than that, maybe even half that amount.
The only way to know how much your particular rock will displace is to dunk it and measure.
abulgin
Premium Member
First things first--don't ever medicate your tank. Move animals to QT and dose in QT. If you dose in your tank, your rock will absorb that medication and release it back into the tank.
Second, I'm not sure I understand the statement that denser rock displaces less water. Displacement is, first and foremost, a function of the volume of the thing that is immersed in water. Thus, something that sinks will displace more water than something that floats. Every rock we use in our aquariums is going to be heavier than water and is, therefore, going to sink. However, live rock that is porous is going to absorb some of that water rather than displace it, so I think it's fair to say (although I have no scientific proof) that a very porous rock, like Fiji, will probably displace less than a less porous rock, like slab. Maybe the practical effect is the same, however, because maybe at the end of the day you have X gallons of water swishing around the tank regardless of what kind of rock you use.
With all that said, I don't think there is an easy way to accurately guage how much water your rock displaces. You'd have to calculate/figure out the volume of your rocks. You can't do it by weight or density alone. A pool ball that sinks will displace exactly the same volume of water as a piece of iron ore of the same volume.
Second, I'm not sure I understand the statement that denser rock displaces less water. Displacement is, first and foremost, a function of the volume of the thing that is immersed in water. Thus, something that sinks will displace more water than something that floats. Every rock we use in our aquariums is going to be heavier than water and is, therefore, going to sink. However, live rock that is porous is going to absorb some of that water rather than displace it, so I think it's fair to say (although I have no scientific proof) that a very porous rock, like Fiji, will probably displace less than a less porous rock, like slab. Maybe the practical effect is the same, however, because maybe at the end of the day you have X gallons of water swishing around the tank regardless of what kind of rock you use.
With all that said, I don't think there is an easy way to accurately guage how much water your rock displaces. You'd have to calculate/figure out the volume of your rocks. You can't do it by weight or density alone. A pool ball that sinks will displace exactly the same volume of water as a piece of iron ore of the same volume.
Last edited:
MotherFish
New member
You should be fine ballparking the figure at about twice the density of seawater, or about 6 gallons.
Btw, before medicating your entire display tank you may want to post over in the disease forum for advice. Depending on what you're treating for, it may be preferable to treat in a separate hospital tank.
*edit* You're too quick or me. :lol:
Btw, before medicating your entire display tank you may want to post over in the disease forum for advice. Depending on what you're treating for, it may be preferable to treat in a separate hospital tank.
*edit* You're too quick or me. :lol:
