Go Back   Aquarium Advice - Aquarium Forum Community > Saltwater and Reef > Saltwater Reef Aquaria
Click Here to Login

Join Aquarium Advice Today
Reply
 
Thread Tools Search this Thread Display Modes
Please support our sponsors and let them know you heard about them on AquariumAdvice.com
 
Old 04-18-2004, 12:15 PM   #1
KLN
Aquarium Advice Regular
 
Join Date: Nov 2003
Location: Florida
Posts: 75
water displacement of sand and rock

Does anyone have a rough formula for water displacement of sand and rock by weight? I have about 40 pounds of sand and 60 pounds of rock in a 55, and want to know how much water I have. 45 gallons, perhaps?
__________________

__________________
KLN is offline   Reply With Quote
Old 04-18-2004, 12:30 PM   #2
Aquarium Advice Addict
 
Join Date: Sep 2003
Location: Lompoc, Ca
Posts: 1,313
Send a message via AIM to XXFirefighter Send a message via Yahoo to XXFirefighter
I got 55 pounds of live sand and 90 pounds of life rock and 45 gallons filled my 55 PERFECT !
__________________

__________________
XXFirefighter is offline   Reply With Quote
Old 04-18-2004, 09:01 PM   #3
Aquarium Advice Addict
 
Biggen's Avatar
 
Join Date: May 2003
Location: Panama City FL
Posts: 1,817
Saltwater weighs approx 8.5 lbs per gallon. So if you have 100lbs of rock and sand in a 55 gallon, you are displacing approx 11 gallons of water. So you have roughly 43 gallons of water in the tank.

This actually isn't exactly right because displacement refers to volume and NOT weight but its a good estimate.
__________________
Rodman
Biggen is offline   Reply With Quote
Old 04-18-2004, 10:44 PM   #4
Aquarium Advice Freak
 
Join Date: Jan 2004
Location: Dallas, TX
Posts: 426
The problem with that calculation is that you are using the weight of the water, not thh weight of the sand and rock. Sand and rock is far more dense than water and as such would displace less water by weight. You need to know the approximate size or volume of the sand and rock to measure its displacement, the weight is really irrelevant.
__________________
Hook'em Horns!
MadManMac is offline   Reply With Quote
Old 04-19-2004, 08:40 AM   #5
Aquarium Advice Addict
 
Biggen's Avatar
 
Join Date: May 2003
Location: Panama City FL
Posts: 1,817
Quote:
The problem with that calculation is that you are using the weight of the water, not thh weight of the sand and rock. Sand and rock is far more dense than water and as such would displace less water by weight. You need to know the approximate size or volume of the sand and rock to measure its displacement, the weight is really irrelevant.
That is why I quantified my statement with:

Quote:
This actually isn't exactly right because displacement refers to volume and NOT weight but its a good estimate
__________________
Rodman
Biggen is offline   Reply With Quote
Old 04-19-2004, 09:50 AM   #6
KLN
Aquarium Advice Regular
 
Join Date: Nov 2003
Location: Florida
Posts: 75
I was guessing the sand and rock to be twice the density of saltwater for the calculation, but wondered if anyone had a better guestimate.

Just found this tidbit: water weighs 8.3452641 pounds per gallon. Saltwater would then weight that times 1.025 or 8.55 pounds per gallon, I reckon.

So if I have 100 pounds of stuff twice the density of water, it would displace 50 pounds of water, or about 5.8 gallons of water. I would have guessed it was more than that, like someone said above
__________________
KLN is offline   Reply With Quote
Old 04-19-2004, 11:50 AM   #7
AA Team Emeritus
 
BillyZ's Avatar
 
Join Date: Apr 2003
Location: Western NY
Posts: 4,064
the sand will be pretty easy to figure out and should be rather consistent from tank to tank. The LR, however, will very greatly depending on the type of rock, FL aquacultered, to tonga and even from piece to piece. The easiest way to tell how much your LR is taking up is to measure the amount of change in water level in your tank when you add the LR.

How to determine density Sand:
1)Take a graduated container with a known volume of water (a large glass pyrex measuring cup with 2 cups of water would work well)

2)Weigh out a known amount of dry sand, say 8 ounces (1/2 pound).

3)Add that sand to the measuring cup and note the rise in water volume.

4)Your density is then 8 ounces per (the change in the level of the measuring cup)

NOTE: 16 ounces = 1 pound and 16 cups = 1 gallon.

Example: If 8 ounces took up 1 cup (just speculating) then the density of dry sand would be 8 pounds per gallon. so a 50 pound bag of sand would then take up 6.25 gallons of volume. So as soon as someone has the opportunity to apply this to some dry sand you'll have your answer for the sand )
__________________

__________________
Acronyms and Abbreviations
BillyZ is offline   Reply With Quote
Reply

Tags
rock, sand

Please support our sponsors and let them know you heard about them on AquariumAdvice.com

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
sand or rock? ahollland92690 Freshwater & Brackish - General Discussion 31 10-05-2009 11:13 AM
Which goes in first? Rock or Sand? litebrite Saltwater & Reef - Getting Started 9 05-10-2008 06:57 PM
couple questions...lights & rock displacement sirfishmaster Saltwater Reef Aquaria 6 02-06-2005 02:30 PM
LR Displacement Ratio OneBowl Saltwater Reef Aquaria 6 10-28-2004 12:23 PM
water displacement by LR swishyfishies Saltwater Reef Aquaria 7 04-30-2003 02:08 AM







» Photo Contest Winners








Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -4. The time now is 04:16 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.