Math help.

[Reef.]

Anyone help with a Math formula question?

Trying to work out the salinity (in SG) of my tank after a certain volume of evaporation has taken place...so say the tank was at 1.0264 then after a days evaporation of a known volume, (without topping off) what would the new salinity be?

 

[Jay Hemdal Verified Community Expert]

Anyone help with a Math formula question?

Trying to work out the salinity (in SG) of my tank after a certain volume of evaporation has taken place...so say the tank was at 1.0264 then after a days evaporation of a known volume, (without topping off) what would the new salinity be?

That is a specific gravity reading, and measures the relative density of the water. I think if you were to work with true salinity (parts per thousand) it would be more straightforward. So - if the tank is at 35 ppt, and you remove 70 grams of water through evaporation, then the solution would be at 35 parts of salt in 900 parts of water.

Chemistry of solutions is tough for me though, you might try posting in the water chemistry forum...

Jay

 

[KStatefan]

Anyone help with a Math formula question?

Trying to work out the salinity (in SG) of my tank after a certain volume of evaporation has taken place...so say the tank was at 1.0264 then after a days evaporation of a known volume, (without topping off) what would the new salinity be?

Resulting Salinity Calculator

Aquarium calculator; Estimate the resulting change in salinity when water is added, replaced, or evaporated.

www.hamzasreef.com

I think to do the math you would have to convert to ppt the math should be simple when using ppt

Current 35 ppt
Tank Volume 100 gallons
Evaporated 5 gallons

35/((100-5)/100)

35/.95 = 36.8

 

[Randy Holmes-Farley Verified Community Expert]

In specific gravity, it essentially works if you ignore the leading 1.

In the above example:

Current sg = 1.026
Tank Volume 100 gallons
Evaporated 5 gallons

26/((100-5)/100)

26/.95 = 27.4

new sg = 1.0274

 

[Jay Hemdal Verified Community Expert]

In specific gravity, it essentially works if you ignore the leading 1.

In the above example:

Current sg = 1.026
Tank Volume 100 gallons
Evaporated 5 gallons

26/((100-5)/100)

26/.95 = 27.4

new sg = 1.0274

Thanks, I always wondered if that worked, but never was sure.
Jay

 

[Reef.]

In specific gravity, it essentially works if you ignore the leading 1.

In the above example:

Current sg = 1.026
Tank Volume 100 gallons
Evaporated 5 gallons

26/((100-5)/100)

26/.95 = 27.4

new sg = 1.0274

Brilliant, thanks for that.