Online Tank Calculator

[jasengt]

Calculates the Real Voume of water in your tank, how much you need to add based on the information you provide. Takes into account the sand bed, and how much rock is in the tank. Will calculate out the exact specific gravity of the water you need to add, and how much you need to add. It is a great tool, and it should be very close to what you need to do. Uses highly scientific calculations, and its fast! Takes into account the big items that limit the exact amount of water in your tank.

Check it out: http://www.jasenhicks.com/tideline/tankcalcs.php

- Jasen

 

[Dale W.]

Not quite sure if I like it or not. It gives a pretty good average of what we probably already know but there is way to many variables to concider with this.

 

[jasengt]

I'd like to make the calculator as accurate as possible, any more inputs that anyone would reccomend?

 

[Dale W.]

What is the purpose of this calculator? I didnt mean to sound like I was puting it down by the way. I am just trying to figure out its needs.

I also figured it out on my 150g tank and it said that I only have 80 gallons of water so I am not sure how accurate that is. Another thing to concider since you posted it in the marine section is the use of a sump(volume), protien skimmer(volume) and any other filter used that migh add water volume. Also the porosity of LR varies greatly and one that weighs10lbs from one region may use twice the volume as one from another region.

Maybe list how you came up with the figures that you are using to get a more accurate measurement of dif types of rock etc.

 

[jasengt]

Basically the way it works, is live rock all weighs somthing. Based on some information i found about most marine rock that is used in saltwater tanks i found out the density of the rock, if a rock weighs 5lbs, and its density is 5lbm/ft3 that means it displaces 1 ft3 worth of water. Regardless of the porosity its going to displace that much water. I also used the fact that if there is sand or a bed in the tank, it essentially shrinks the height of the tank by however deep the bed is, so if you have measrued 4 different parts of the bed, it averages it out, subtracts it from the height of the tank. Then it calculates the volume of the tank, and subtracts off the water that the rock displaces, and voila you have the actual amount of water in your tank. Id venture to say that if you ever drained your tank as is, and measrued the water you took out, it would be rather close to 80gallons. Some conversions i used: 231 cubic inches in 1 gallon (liquid), denisty of water 62.4 lbm/ft3, specific gravity (how much more dense than water the rock is) 1.025. For the calculations of the water specific gravity i used the : ConcentrationInitial*VolumeInitial + ConcentrationAdd*VolumeAdd = ConcentraitionFinal*VolumeFinal.

Hope this gives insight to how it all works.

 

[frosty]

This isnt exactly rocket science, assuming his math is all correct I would venture to say the calculator is accurate enough. I do think you should add sump volume, maybe even filter volume.

PS.
Jasengt - Have you actually tried it on your tank?

Also I would agree that different rock will displace different amount of water, but most likely neglible variance.

 

[jasengt]

I tried it on my 20 gallon tank, and it came out pretty well. When i set it up i used 20 gallons of water for my sea salt add, and the specific gravity was way too high, why? Beacuse i didnt account for the gravel bed! Duh! Adding the sump/filter volume is a great idea, i didnt think of it because i dont have a sump for my lil 20 gallon salt tank. That's going to have to be added. As far as the rocks are concerned I dont think everyone is fully grasping the concept of how i did this, but its ok, its hard to explain anyways.