Need formula to reduce density/salinity

[Jimboo]

Hello,

i prepared an excel file to calculate and track my water changes.

Actually i am struggling to find a formula to calculate the following:

Density in my tank is 1,0240 CM³/ 37,24 psu and i want to calculate the amount of freshwater(water change in liter/oz) required to reach 1,0232 CM³/ 34,86 psu.

Can anyone help me with that please?

Regards

Jimboo

 

[ReeferNoob4ever]

Maybe do it manually one time, note the procedure and create a formula accordingly.

 

[billdogg]

That sounds like way too much work. Why not just mix some up at slightly less than your target value (which, btw, is actually a bit low for most corals) and go from there?

 

[SFish]

Why are you using density?

 

[2una]

https://www.hamzasreef.com/Contents/Calculators/ResultingSalinity.php

 

[ReeferNoob4ever]

Nice link.

 

[SFish]

You would have to figure out the density of a solution of salt at the proper concentration. Mix up a L of salt at the proper concentration. The salt is part of the L so don't use a L of water then add salt. From there you can figure out how much salt you need in a L.

Ex (just making up numbers)

Lets say there are 500g in 1L to get you at an SG of 1.026

So say you want to make 4L

4L (500g/L)=2000g of salt you would need keep in mind that the 2000g is part of the 4L

 

[nereefpat]

It's not too bad. We just calculate what % the new density is of the old density. Then 1 minus that % times total water volume of the tank.

23.2 ÷ 24= 0.9666
1 - 0.9666= 0.0334
0.0334 x total tank volume is how much saltwater you will replace with freshwater.

So about 3 1/3 gallons for a 100 gallon tank.

 

[SFish]

that sounds like way too much work. Why not just mix some up at slightly less than your target value (which, btw, is actually a bit low for most corals) and go from there?

+1