Is there a formula (or chart) somewhere?

[sssnake]

..to show how much volume of water (and at what salinity) is needed to raise the salinity level of your tank so as to avoid the "trial and error" method?

Example:
120g tank needs 10g to raise the SG from 1.022 to 1.024

[reef_guru]

good luck

[Matt Rogers]

Originally Posted by sssnake

..to show how much volume of water (and at what salinity) is needed to raise the salinity level of your tank so as to avoid the "trial and error" method?

Example:
120g tank needs 10g to raise the SG from 1.022 to 1.024

This is what I have found...

system volume: 125 gallons
sg: 1.025

desired sg: 1.023
water change (volume of new water: 50 gallons)


How to calculate sg of new water:

(50 x S) + (75 x 1.025) = 125 x 1.023

=> S = ((125 x 1.023) - (75 x 1.025))/50

= 1.020

http://www.fizzwizz.net/salcalc.xls



Also of interest:


CNYKOI - Salinity calculator

SaltyZoo's Evaporation effects on salinity calculator

Aquaculture Species Salinity Calculator for Western Australia

Originally Posted by reef_guru

good luck

Does this help?

[sssnake]

You're the best Matt!

Thanks a million.

[Matt Rogers]

No prob.
After the holiday I will try to make a web app with that formula and add it to the calculator page.

[Camilsky]

Matt! One thing ! Please include the reference temperature, at which you perform the calculation and mixing! The salinity will drop with the increase of temp...! As we all know

[Matt Rogers]

Originally Posted by Camilsky

Matt! One thing ! Please include the reference temperature, at which you perform the calculation and mixing! The salinity will drop with the increase of temp...! As we all know

Interesting... how would I do that sir?
As a footnote? Or part of the equation?

[Camilsky]

Originally Posted by Matt Rogers

Interesting... how would I do that sir?
As a footnote? Or part of the equation?

Hmm, a footnote would do the trick. (Something like: Starting from 1.024 g/cm3 at 25C). I don't have it with me right now, but I remember there is a chart that one could use to predict what is the expected density of marine water at different temperatures if you know the salinity at 25C.

[reef_guru]

camilsky thats why i said good luck, temp effect salinity along with Ca and everything else. baby steps. if my salinity goes down in the main tank i just add a little in the overflow and give it 24 hrs, if its still a little low i add a little more. to much and theres problems. and i havent had to do that in over a year.

my concern is why is the salinity dropping. if its not dropping then dont worry about it. if you dont have an overflow take out about 2 cups of water and add a tablespoon of salt, mix then pour back in an area with alot of flow. this isnt rocket science.