Dozey

Just wonder if any one knows how much water a pound of gravel disburses. Knowing this would certainly help me and I’m sure others, determine a truer tank size. I’ve read that a general rule of them is to use about 1 lbs of gravel per gallon of tank size.

I’ll try to explain myself a little better. It has been suggested to me that if I have a 20 gallon tank I should plan to add 20 lbs. of gravel. So I’d like to know how many gallons of water I would have in a 20 gallon tank after adding 20 lbs. of gravel.

It sure would help when deciding how to stock a tank without over-stocking it.

Charmaine

I,m not sure about the gravel but one way to check on how to stock your tank is to take the siz of the fish you want and multyply his body length by 6, that is the swimming space needed for your fish to have more than enough space to move around.
The less room your fish have the grumpier they will be.

Dozey

Thanks Charmaine but that is exactly why I'm asking the question. “One inch of fish per gallon of water”, “fish’s size times 6”. If we knew the actual size of a tank after adding gravel is would certainly help in making informed decisions.

I know that other décor and plants also disburses water but obviously the gravel is the major contributor.

Perhaps I should add that it would help in other areas such as medicating a tank. If the instructions suggest 1 tablespoon per 10 gallon of water and I have a 50 gallon tank then how much water do I actually have after adding 50 lbs. of gravel? 45 gallons? 40 gallons maybe?

gonzo127

thats a very hard question, especially since different gravels will have a different densitie's, therefore you will require more of one type of gravel to get to a set weight than you would another.

i think a good way of looking at this would be to take a hight measurement at the front of the tank and one at the back (to take into account the slope most people have) add them together, half the result, submit said figure into the 'hight' section of the tank size calculator on this site with the length and width added in would give you a rough idea on the max volume of displaced water, then if you want to take into account the fact that you will have water inbetween the prices of gravel you can always take 10-15% off

however this is probably not the most accurate way of doing it, i just cant think of a better way to work it out

gonzo127

the other way to do it which i beleive most people on this site seem to do is take your maximum size of tank, in your instance 50 gal, then just allow a certain % safety margin for example 10% - 15% on a smaller tank due to the more 'unstable' nature of a smaller tank and maybe a 5-10% margin on a bigger tank

Dozey

Thanks Gonzo, I think you might just have hit on the simplest method. Deduct the height of the gravel from the over all height of the tank. That's close enough for me. What ever little bit of water is in the gravel likely is not all that significant. Thanks for the suggestion.

Butterfly

Will this help any? http://reef.diesyst.com/volcalc/volcalc.html
carol

Dozey

Thank you Carol for the link, you bet that will help.

Butterfly

Welcome I've used it before and seems accurate.
Carol