Dosing only alkalinity

[Paul31733]

Hey everyone!
Well it seems I have made it to the point where I am needing to start to dose.
Funny thing is my tank seems to be only lowering alkalinity. Calcium and mag have stayed stable.
Is this normal?
Could my dkh test be off?
I have not been having much of a drop.
Around 0.2dkh per day.
Guess I am wondering if this is normal.
Thanks.
Paul.

 

[Randy Holmes-Farley Verified Community Expert]

Funny thing is my tank seems to be only lowering alkalinity. Calcium and mag have stayed stable.
Is this normal?

That's always the perception because alkalinity always falls much faster, on a percentage, basis than does calcium. You just cannot detect the others appropriately.

At 0.2 dKH alk decline per day, calcium decline is (at most) only about 1.4 pm per day, and magnesium is more like 0.1 ppm per day or less. It is impossible to detect those declines with kits unless you monitor over a very long time, and water changes will mess up that monitoring.

 

[Paul31733]

That's always the perception because alkalinity always falls much faster, on a percentage, basis than does calcium. You just cannot detect the others appropriately.

At 0.2 dKH alk decline per day, calcium decline is (at most) only about 1.4 pm per day, and magnesium is more like 0.1 ppm per day or less. It is impossible to detect those declines with kits unless you monitor over a very long time, and water changes will mess up that monitoring.

Thank you for your detailed reply.
Is it ok for me to dose small amounts of alkalinity to try to achieve stability or will this mess with my other parameters.

 

[New&no clue]

Following along as I have the same thing. My alk drops about .2-.3 a day while my calcium and mag never change. I've been dosing just Alk for about 3 months now. However, I did notice one time my salt mixed really high for Alk, I typically keep it around 8.5 and it mixed it 9.5 then my Calcium started to drop. I think I read this somewhere, but not sure, that if you want accelerated growth to have a higher Alk. Which would make sense to me why if Alk is higher and promoting accelerated growth that your calcium would also be used in that growth and would drop quicker.