Habitat - Indoor :: Rule of thumb for how much sand you'll need.

[Chrisbarnett]

How much sand will I need?
I figured out a basic rule of thumb calculation to go by. so just try this out. Multiply the size of your tank in gallons, by .425 and then round up or down to the nearest bag size of sand. Sand usually gomes in 10, 20, 25, and 50 lb bags.
so say you have a 55 gal tank, the calculation would be 55x.425, you get a number of 23.375, now round that up to 25 and you see that you'll need 25 lbs of sand for your tank.
Lets do it now with a 125 gal tank, 125x.425, you see that you come up with 53.125, so round that down to 50, and you have the common bag size of sand that you'll need.

I came up with that by dividing 50 by 125, and 25 by 55, then adding the 2 numbers together, then averaging them out.

This calculation would be for 1-2" of sand depth on average.

So what do you guys think? That sound like a good rule? Or should I change my numbers around??

This Q&A is posted in the SandFAQ thread now, but wanted to get input on it here..

Thanks.

[mh_sac]

This is a good thread Chris! If you don't mind, I would like to tender another formula:

(Volume of the sand bed in inches)(0.0643)

IE: For a 55 gallon tank (dimensions 48''x12'') with a desired sand depth of 1'', the weight of sand needed would be: (48 in x 12 in x 1 in)(0.0643 lb/in^3) = 37 lb

Factors to consider:
1) The formula uses a generic sand density. A more accurate figure can be attained by searching for and using the density of the specific sand one is considering of purchasing.
2) The calculation assumes uniform depth.
3) The density is for DRY sand. Wet and compacted sand will have a larger density and for a given weight of sand, wet and compacted sand will yield a shorter depth (probably negligible for the most part).

Derivation Rationale: Simple google search yielded an average dry sand density of 1780 Kg/m3 (source: http://wiki.answers.com/Q/What_is_the_density_of_sand; i know, not the most reliable source, but probably close enough). Converting this to lb/in^3 gives 0.0643 lb/in^3. Therefore, by multiplying the area of the tank by the height of the sand (or simply the volume of the sand bed) by the average density will render the weight in pounds (lb).

It's early and I'm tired, please correct me if a flaw is discovered in my logic. Thanks.

[zoologist]

you're both insane. just so you know.

[Daniel3507]

yeah that sounds.........great? i guess

[Selera]

I think some people are being a little too thoughtful on formulas. What are you two mathmeticians?

[Chrisbarnett]

I think you kinda lost me there MH, but doing it on the calculator everything comes out and makes sense. But that's a lot more sand than I used for my 55 gal, I used 25lbs or so and I have an average depth of 1-2", although you said that was for dry sand...Hmm.

I think for now, I'll keep up the simpler conversion I originally posted so that anyone with super basic calculator or basic math skills could figure it out quick and easy, then just round up or down to the nearest common bag size.

Anyway, I'm not a mathmetician! lol, I got like a B- in Geometry last year, then now in Junior year, I'll be taking advanced algebra which confuses the crap outta me...

[Daniel3507]

just wait till college algebra. least favorite class EVER

[untsmurf]

I was a math major in college and I would tend to side with Chris's formula. It's easier for everyone to understand and seems to be pretty accurate. Just to simplify it even more you might want to make a chart that explains when to round up and when to round down.

[mh_sac]

While I don't believe my formula is very complicated, I do agree Chris' formula is easy, practical and serves as an excellent rule of thumb. I just thought of throwing mine out for those interested in depths other than 1-2'' and unorthodox tank dimensions (relative to its respective standard dimensions).

If we wanted to really make it simple, instead of creating a table to convey when to round up/down, we can just simply create a size-to-weight correlation table. This way, math and redundancy can be avoided completely.

Also, I would like to thank Chris for his efforts on the sand FAQ. It appears to be a growing trend amongst us, and the FAQ will serve as the foundation for the new, curious and perhaps tentative owners (myself included).

Take care everyone!

[Chrisbarnett]

If we wanted to really make it simple, instead of creating a table to convey when to round up/down, we can just simply create a size-to-weight correlation table. This way, math and redundancy can be avoided completely.

Also, I would like to thank Chris for his efforts on the sand FAQ. It appears to be a growing trend amongst us, and the FAQ will serve as the foundation for the new, curious and perhaps tentative owners (myself included).

Take care everyone!

MH, I am interested in the simple size-weight correlation table you mention. Could you please elaborate on that?

Your welcome, and thank you for the kind words

[Daniel3507]

i thought my way of finding out how much sand i needed was easy. i added some and if i thought i needed more i would go get more. haha.

[mh_sac]

i thought my way of finding out how much sand i needed was easy. i added some and if i thought i needed more i would go get more. haha.

I think Dan bested all of us.

[mat012]

i thought my way of finding out how much sand i needed was easy. i added some and if i thought i needed more i would go get more. haha.

I think Dan bested all of us.

Yeah this was close to my method as well. Oh 50 lb bag - well lets use 50 lbs! Lucky my tank was big! I could have had half a tank full of sand!

[PcBuilder14]

I've got a 10 gallon tank with 20 lb's of sand!!! A little to much sand for me. I was only going to use half and I slowly added more, then I ran out of sand!LOL