Why is my tank not consuming Calcium?

[*HOVA*]

I've had my tank up and running for about a year and a half and have been adding coral for about 6-8 months now. My tank is using about 15ml of Alk a day to maintain 8.6 but my Ca and Mg stay consistently high with Ca over 480 and Mg over 1480. I have a Red Sea Reefer 525 which is about 140G total volume and I change about 20% water weekly and use HW Reefer salt. I expected my fairly large WC to help keep up with dosing needs but I have yet to dose any Ca since I set my tank up.

Are my WC's just doing that good at keeping up or what could be the cause of no Ca consumption in my tank?

 

[AdamB]

Normal .what types of coral are you stocking ? Looks like your water changes are keeping up with calcium and mag.
Your alkalinity will always decline much faster than calcium and mag. I only check my alk once a week and check others once a month or longer.If I see a change in my alk I will test calcium and magnesium.
I dose 2 part with doser on my setup.

 

[smartwater101]

What test kit are you using for ca/alk/mag, and have you confirmed with another brand test?

20% weekly will likely keep ca in line especially if you dont have any large corals.

 

[The Aquatic Arsenal]

You want to lower your magnesium level.

The Role of Magnesium in Marine Aquarium Chemistry

One of the big differences in moving from freshwater systems to saltwater systems is a greater emphasis on water chemistry. There is a pretty steep learning curve to get a handle on all the differe…

www.saltwatersmarts.com

 

[Bayareareefer18]

I had the same issue until my coraline population exploded

 

[*HOVA*]

I have a Trident and I also test with Salifert against it weekly to ensure it's properly calibrated.

I'm not sure how I would reduce Mg? I don't want to complicate things if I don't need to... I've seen people run elevated numbers with no issue so I'm not sure I'm at a terribly high number where that's a concern?

 

[*HOVA*]

Also, I have almost all SPS. Most frags are a few inches with some larger mini colonies.

 

[benboarder90]

if everything is doing well i would keep doing what you are doing. my tank is the same way. i like to say don't try to make a HAPPY kid Happy.

 

[becon776]

I am having same issues. dosing 12ml of b-ionic alk and zero Ca or Mg. that is keeping alk level but Ca really doesnt move

 

[Matt1997]

Find out the issue? Was it the trident?

 

[*HOVA*]

Still rarely uses any and coral and coraline are doing great. I dunno! Lol

 

[Troyntu]

My tank is the same exact way. About a year old and I have yet to dose cal.

 

[Gtinnel]

My tank is the same way also. My assumption is that my AWC replaces the necessary amount of calcium. I'm also not using very much alkalinity per day at only .25dKh. I'm assuming at some point as my corals grow bigger I'll have to start dosing both.

 

[Randy Holmes-Farley Verified Community Expert]

My tank is the same way also. My assumption is that my AWC replaces the necessary amount of calcium. I'm also not using very much alkalinity per day at only .25dKh. I'm assuming at some point as my corals grow bigger I'll have to start dosing both.

This sometimes works works out because some salt mixes have excess calcium in them.

At 0.25 dKH per day, you are losing about 51 ppm calcium in a month if all that alk is going into corals or abiotic precipitation, as opposed to nitrate production, etc., which uses no calcium..

To offset that you'd need to change quite a bit with a mix that is well above the stable tank calcium level.

 

[Gtinnel]

This sometimes works works out because some salt mixes have excess calcium in them.

At 0.25 dKH per day, you are losing about 51 ppm calcium in a month.

To offset that you'd need to change quite a bit with a mix that is well above the stable tank calcium level.

I change out about 60 gallons (around 45% of my approximately 140g system) of water each month. I use reef crystals that last time I checked mixed up at 500ppm.
If that isn't enough to account for the 51ppm (I'm not sure how to do the math to tell) then I don't have any idea why I don't need to dose calcium too.

 

[Randy Holmes-Farley Verified Community Expert]

I change out about 60 gallons (around 45% of my approximately 140g system) of water each month. I use reef crystals that last time I checked mixed up at 500ppm.
If that isn't enough to account for the 51ppm (I'm not sure how to do the math to tell) then I don't have any idea why I don't need to dose calcium too.

It depends on the tank value to stabilize at, but at 420 ppm in the tank and 500 ppm in the new salt water, that water change will add about (500-420) x 0.45 = 36 ppm.

 

[Gtinnel]

It depends on the tank value to stabilize at, but at 420 ppm in the tank and 500 ppm in the new salt water, that water change will add about (500-420) x 0.45 = 36 ppm.

My Calcium in my tank generally runs high at about 480 which would mean that my water changes would only add 9ppm. So I have no idea why I don't have to dose calcium. I will likely buy a second test kit to confirm my reading and then I guess not worry about it until I start seeing it decline.

 

[Randy Holmes-Farley Verified Community Expert]

and then I guess not worry about it until I start seeing it decline.

That's reasonable.