Water displacement quiz!!!!!!

[Troylee]

So as you all know I'm taking down my big 220 display and the other day I sold all the rock.... So I mixed up 60gal of fresh saltwater to replace the the 250 to 300lbs of rock that I was removing.... I get all the Rock out and start adding water back into the tank to keep it level and running since I have a few fish and coral still in there and no homes for them yet.... To my surprise it took "x" amount of water it was really shocking can you guess how much?????? I thought this would be great in helping people who dose this or that and guesstimate there rock displacement when dosing etc..... Answer later I wanted to have a little fun with this...:xd:

 

[turbo21]

im saying 21 gallons.
did you let the rock drip in the tank before totally removing it? or jut pull it out and stick it in a tub

i think we forget how pourus the rock really is

bob

 

[ToXIc]

my brain hurt :squigglemouth:

 

[swannyson7]

Any hints on what kind of live rock? Some are really porous, but I'm going to guess 30 gallons

 

[slice]

It will vary according to the density of the rock. I made a guess and voted, look forward to reading the answer.

 

[EliteReefs]

yea, depends alot on the type or rock. but i guessed 47. heck i removed just three good size chunks from mine the other day and it was enough to start blowing bubbles and i had just added 20 gallons in top off two hours prior.

 

[iap]

I'll guess 40 gallons

 

[johnanddawn]

after a couple quick calculations - the density of rock is about 120lbs/ft3 so about with 17 gallons
not one of your choices but the rock was obviously wet so 21 is the best choice

 

[Troylee]

it was marco rock and yes i let it drip out for the most part.... i found it really odd myself as you see i mixed 60 gal of freshwater up to replace it haha....

 

[Captain Nemo]

I say it's 21 g because we don't know what kind of rock. Tour description was vague Troy.

 

[Viva'sReef]

I voted 30, but I'd like to change my answer to 37.5g LOL

 

[Alkamist]

I'm taking a random guess and say 21 gallons

 

[Troylee]

12 gallons..... that is what it took to top off the tank back to where it was.... it blew my mind i thought for sure a tank that size stuffed with rock would take up more room i mean i had 4 tubs like 3'x2'x2' stuffed to the top with rock and only 12 gal of water was missing:squigglemouth: i mixed up 60gallons that was my guess haha....

 

[turbo21]

wow, you must have been really shaking the water out of the rocks for only 12 gal replacement:hammer:

 

[extremehobbyist]

well im assuming the rock was wet when u put it in so 300lbs divided by 8.3454 which is the weight 1 gallon of water weighs my guess is 35.947

 

[slice]

Someone please check my math here
(I used this for conversion calculations ABE Unit Conversion Calculator )

You say 250-300 lbs of rock, I used 275 lbs.

275 lbs Rock = 12 gal SW (assumed at 1.026 SG)
= 1.60422 cu ft
= 171.42 lbs/cu ft

That sounds like some pretty dense rock. Would you estimate it was roughly 1.6 -ish cubic feet?

 

[johnanddawn]

Someone please check my math here
(I used this for conversion calculations ABE Unit Conversion Calculator )

You say 250-300 lbs of rock, I used 275 lbs.

275 lbs Rock = 12 gal SW (assumed at 1.026 SG)
= 1.60422 cu ft
= 171.42 lbs/cu ft

That sounds like some pretty dense rock. Would you estimate it was roughly 1.6 -ish cubic feet?

your math seems right to me - thats some VERY dense rock (not likely) or there was less weight then estimated

working it backward 120pounds/cu ft and 12 gallons of water = only about 200 pounds of rock

 

[Troylee]

At the least 230lbs I would say 275 ish.... It was very strange to me thats why I posted this lol... You can see my intentions I inttially mixed up 60gal of water thinking that I was close...

 

[Troylee]

Btw it's that Key largo rock that I bought from Marco awhile back.. I bought 200lbs and added a few pieces from another tAnk I had so I know for sure it's 200 minimum unless I didn't receive 200 I never weighed it haha..

 

[johnanddawn]

it is very interesting - i'm glad you posted it because i have never really done the math before either
i found a site that said solid limestone can be 163pounds / cubic foot which puts you about there, i just would have though that it would be less dense then that - maybe its because it is marco rock and that stuff is basically cement right?