Have you ever tested your tank salinity and found it to be too high or too low? I know I have. I hated guessing what salinity water I had to use to increase or decrease my salinity to the desired level. Well guess no longer, friend. I'm sure this formula is used for other things, but I figured it out with the help of my beautiful wife and some deduction so I wouldn't have to guess anymore. I've tested it many times and it always gives the correct answer. For the sake of not putting out the longest read in Reef2Reef history, I won't include changing from a lower salinity to a higher salinity, but rest assured it works.
***Keep in mind, when adjusting salinity, all other major/minor/trace elements will be rise/fall depending on the direction you go. This is used solely for the purpose of changing the salinity.***
Here it is:
((A(t-r)+(t-R)C)/t=D
A=Current Tank Salinity
C=New Water Salinity
t=Total aquarium volume
r=Removed volume of water
R=Remaining volume of water
D-Desired Salinity
(edited)
Here's are some examples of it working.
Say you have a 80 gallon tank, the salinity is sky high at 1.030, and you're wanting to do a water change to correct it. You choose the desired amount of water you want to change, use this formula, and you'll never have to guess. For this example, we'll change out 10 gallons of water and target a salinity of 1.026. You'll just use the order of operations and voila. In this instance, when you're changing out water, you're solving for "C".
((1.030(80-10)+(80-70)C)/80=1.026
((72.1+10C)/80=1.026
72.1+10C=82.08
10C=9.98
C=.998
Now we'll plug it in to make sure it works. You'll use the 2nd step in the formula to answer for confirmation. This just stops you from having to redo math.
(72.1+10x.998)/80=1.026
82.08/80=1.026
1.026=1.026
BUT WAIT, THERE'S MORE. You can also use it to determine how much saltwater to remove and replace with RODI water at 0 salinity. You don't have to change out the water if you don't want to. In this example, we're solving for "r".
((1.030(80-r)+(80-R)0)/80=1.026
(1.030(80-r))/80=1.026
(82.4-1.030r)/80=1.026
82.4-1.030r=82.08
-1.030r=-0.032
r=0.31067961165048543689320388349515
Now only for the sake of the equation am I copying the entire answer. You don't need to be so accurate when you're adding the water.
Now we plug in the number we got for "r" into our original formula for adding RODI.
((1.030(80-0.31067961165048543689320388349515)+(80-R)0)/80=1.026
((1.030*79.689320388349514563106796116505)/80=1.026
82.08/80=1.026
1.026=1.026
TL;DR- The formula works. I just wanted to show you that it worked. No more guessing, no more over/under adjusting. Good luck and happy reefing!
***Keep in mind, when adjusting salinity, all other major/minor/trace elements will be rise/fall depending on the direction you go. This is used solely for the purpose of changing the salinity.***
Here it is:
((A(t-r)+(t-R)C)/t=D
A=Current Tank Salinity
C=New Water Salinity
t=Total aquarium volume
r=Removed volume of water
R=Remaining volume of water
D-Desired Salinity
(edited)
Here's are some examples of it working.
Say you have a 80 gallon tank, the salinity is sky high at 1.030, and you're wanting to do a water change to correct it. You choose the desired amount of water you want to change, use this formula, and you'll never have to guess. For this example, we'll change out 10 gallons of water and target a salinity of 1.026. You'll just use the order of operations and voila. In this instance, when you're changing out water, you're solving for "C".
((1.030(80-10)+(80-70)C)/80=1.026
((72.1+10C)/80=1.026
72.1+10C=82.08
10C=9.98
C=.998
Now we'll plug it in to make sure it works. You'll use the 2nd step in the formula to answer for confirmation. This just stops you from having to redo math.
(72.1+10x.998)/80=1.026
82.08/80=1.026
1.026=1.026
BUT WAIT, THERE'S MORE. You can also use it to determine how much saltwater to remove and replace with RODI water at 0 salinity. You don't have to change out the water if you don't want to. In this example, we're solving for "r".
((1.030(80-r)+(80-R)0)/80=1.026
(1.030(80-r))/80=1.026
(82.4-1.030r)/80=1.026
82.4-1.030r=82.08
-1.030r=-0.032
r=0.31067961165048543689320388349515
Now only for the sake of the equation am I copying the entire answer. You don't need to be so accurate when you're adding the water.
Now we plug in the number we got for "r" into our original formula for adding RODI.
((1.030(80-0.31067961165048543689320388349515)+(80-R)0)/80=1.026
((1.030*79.689320388349514563106796116505)/80=1.026
82.08/80=1.026
1.026=1.026
TL;DR- The formula works. I just wanted to show you that it worked. No more guessing, no more over/under adjusting. Good luck and happy reefing!
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