Salinity relation to Dosing

[merfury1989]

Hi all,

I always wondered about something when it comes to dosing.

If my salinity is 35ppm, and I maintain 8dkh Alkalinity and 430ppm Calcium --- From Red Sea Salt (Not Coral Pro Salt)

And say after 1 week when i check my Alk, Cal, and Salinity levels, they come to:

Salinity = 34ppm
Alk = 7.5dkh
Cal = 410ppm

How much I actually need to dose? to reach same levels as before (Alk 8, Cal 430), and then what happens if I raise salinity back to 35ppm?

 

[Randy Holmes-Farley Verified Community Expert]

Hi all,

I always wondered about something when it comes to dosing.

If my salinity is 35ppm, and I maintain 8dkh Alkalinity and 430ppm Calcium --- From Red Sea Salt (Not Coral Pro Salt)

And say after 1 week when i check my Alk, Cal, and Salinity levels, they come to:

Salinity = 34ppm
Alk = 7.5dkh
Cal = 410ppm

How much I actually need to dose? to reach same levels as before (Alk 8, Cal 430), and then what happens if I raise salinity back to 35ppm?

If you raise salinity from 34 to 35, everything rises by a factor of 35/34 =1.0294.

Thus, the alk hardly moves, 7.5 to 7.7 dKH, and calcium rises from 410 to 422 ppm.

Bear in mind that the salinity change is near the limit of test accuracy, as are the other two changes.

 

[merfury1989]

So in theory, when i want to dose Alk, I need to compensate change in Salinity? Instead of dosing 0.5dkh, I should be dosing 0.25dkh? Which takes my Alk to 7.75dkh @ 34ppt (and would be around 8dkh @ 35ppt)?

If you raise salinity from 34 to 35, everything rises by a factor of 35/34 =1.0294.

Thus, the alk hardly moves, 7.5 to 7.7 dKH, and calcium rises from 410 to 422 ppm.

Bear in mind that the salinity change is near the limit of test accuracy, as are the other two changes.