Increasing salinity - concentration of parameters

Myka · Jan 22, 2017

So 35 ppt is 3.5% salt by weight, correct?

So if someone lists parameters at 33 ppt, then the difference is only 0.2%, correct?

For example, if someone reads salinity at 33 ppt and calcium at say 400 ppm, then if the tank evaporates to 35 ppt, the calcium would be 400.8 ppm assuming no calcium is used up in the tank., correct?

JimWelsh · Jan 22, 2017

No the difference is 1-(35/33) = 6%. If Ca = 400 PPM @ 33 PPT, and that is allowed to evaporate to 35 PPT, then Ca will then = 400 * 35 /33 = 424.3 PPM. In terms of how you were trying to approach the problem, think of the difference as being 0.2 / 3.3, which is also 6% and not just the 0.2% alone.

Myka · Jan 22, 2017

JimWelsh said:
No the difference is 1-(35/33) = 6%. If Ca = 400 PPM @ 33 PPT, and that is allowed to evaporate to 35 PPT, then Ca will then = 400 * 35 /33 = 424.3 PPM. In terms of how you were trying to approach the problem, think of the difference as being 0.2 / 3.3, which is also 6% and not just the 0.2% alone.

Thanks Jim. That makes more sense considering test results. That's why I was asking. My brain said the difference is tiny, my test kits over the years tell me otherwise.