Element Consumption Rate

[RobTorMar]

Hello,

I'm trying to understand a bit more how dosing and element consumption works. My tank currently has about 7 corals and my calcium and magnesium stay relatively constant at 420-450 PPM Ca, and 1500-1600 Mg. I do water changes weekly and maybe this is why I see no fluctuations. But shouldn't the corals be consuming the Ca and Mg? Is there a rule of thumb for number of corals vs dosing requirements? What is the consumption rate of corals?

Any insights would be appreciated!

 

[Randy Holmes-Farley Verified Community Expert]

There's no rule of thumb. Soft corals use almost no alk/calcium or magnesium. Hard corals use them as they grow.

Are you tracking alkalinity? That's the fastest thing to drop when corals use alk/calcium, and magnesium.

 

[RobTorMar]

There's no rule of thumb. Soft corals use almost no alk/calcium or magnesium. Hard corals use them as they grow.

Are you tracking alkalinity? That's the fastest thing to drop when corals use alk/calcium, and magnesium.

I do, alkalinity is the only thing I see fluctuate.... Usually around 8.5 after a water change and 7.5 right before. So it drops 1 pt over a week. Is this normal?