HELP: Calc and Magnesium low

[redseanewbie]

Hello,

So I have noticed that my Calc and Magnesium have been dropping as my Alk has went up. It is now getting to the point where I am starting to panic and need to do something.

salifert tests kit:

Alk: 9.9 Dkh (it was low, 7Dhk so i got it up via dosing)
Calcuim: 320 (was around 400)
Magnesium: 1130 (was around 1200)
Ph; swings from 8.3-8.5 throughout the day
everything else is where it needs to be

I am dosing baking soda that I placed in the oven first.

What should I do? What should I dose?

 

[rishma]

Hello,

So I have noticed that my Calc and Magnesium have been dropping as my Alk has went up. It is now getting to the point where I am starting to panic and need to do something.

salifert tests kit:

Alk: 9.9 Dkh (it was low, 7Dhk so i got it up via dosing)
Calcuim: 320 (was around 400)
Magnesium: 1130 (was around 1200)
Ph; swings from 8.3-8.5 throughout the day
everything else is where it needs to be

I am dosing baking soda that I placed in the oven first.

What should I do? What should I dose?

Were you dosing baking soda and not dosing any magnesium or calccium?

 

[redseanewbie]

I am using Red Sea

Were you dosing baking soda and not dosing any magnesium or calccium?

yes

 

[rishma]

I am using Red Sea

yes

Ok. first…don’t panic, it’s all good.

Calcium, magnesium and alkalinity are generally consumed simultaneously. As your tank uses the alkalinity it also used calcium and magnesium. In general it’s a good practice to dose calcium, alkalinity and magnesium in balanced ratios unless you are correcting one parameter. Here is my favorite fact about the consumption of all three…

For each 2.8 dKH of alkalinity consumed, about 18-20 ppm calcium and 1-2 ppm magnesium are also consumed.

You can dose an appropriate amount of calcium and magnesium to get things back in range. You’ll want continue to dose a balance of all three once you have things corrected.

For calcium and magnesium supplements, do a quick search on 2 part in this forum. Randy and Miami have summarized the recipes in recent threads. You can also buy the stuff you need from bulk reef supply. The calcium and magnesium parts go well with your baking soda.

A word of caution on magnesium test kits, people often find them unreliable. Testing freshly mixed saltwater can be a good way of verifying if your test kit is giving reasonable numbers before you go dosing a lot of magnesium to the tank.

After you have things corrected, it’s a good idea to just dose magnesium in proportion to calcium vs worrying about test accuracy. This is called RMM which has worked well for me and others (quick search of RMM will give you the details)

Best of luck.

 

[rishma]

One more thing, here is a calculator to tell you how much to dose

Reef Chemistry Calculator

 

[redseanewbie]

One more thing, here is a calculator to tell you how much to dose

Reef Chemistry Calculator

Thank you so much. some of my corals are not as open as they usually are and one of my zoa frags are closed so i was starting to worry. I will look into it. The only issue i had is i cant find a 2 part that doesn't raise Alk and i am trying to avoid that since I am already dosing for it. I will search harder

 

[rishma]

Thank you so much. some of my corals are not as open as they usually are and one of my zoa frags are closed so i was starting to worry. I will look into it. The only issue i had is i cant find a 2 part that doesn't raise Alk and i am trying to avoid that since I am already dosing for it. I will search harder

Two part is one part alkalinity and one part calcium. They are two separate solutions. When correcting the calcium, just don’t dose the alkalinity part and it will not raise alkalinity

 

[rishma]

Hello,

So I have noticed that my Calc and Magnesium have been dropping as my Alk has went up. It is now getting to the point where I am starting to panic and need to do something.

salifert tests kit:

Alk: 9.9 Dkh (it was low, 7Dhk so i got it up via dosing)
Calcuim: 320 (was around 400)
Magnesium: 1130 (was around 1200)
Ph; swings from 8.3-8.5 throughout the day
everything else is where it needs to be

I am dosing baking soda that I placed in the oven first.

What should I do? What should I dose?

Had one other thought. If your calcium dropped from 400 to 320 then your magnesium would have only dropped 4-8 ppm.

 

[Randy Holmes-Farley]

I don't trust magnesium testing, but if it is actually in the 1100-1250 ppm range, that can be from low salinity.

What salt mix and what salinity do you have, and measured how?

 

[rishma]

^thats a good point

 

[redseanewbie]

I don't trust magnesium testing, but if it is actually in the 1100-1250 ppm range, that can be from low salinity.

What salt mix and what salinity do you have, and measured how?

1.025 salinity. I use a refractometer that I calibrate often.

Red Sea Blue bucket.

I will say I have started dosing Calcium Chloride in "smaller" doses and pulled my calcium back up to 340ish so i feel a lot better and will continue to tinker.

Lost a single hammer head from the colony which made me panic but everything seems alright

 

[charleydavis]

I am using Red Sea

yes

Baking soda is Sodium Bicarbonate. It does not contain any Calcium or Magnesium. Your coral “eat” or rather consume Ca and Mg so it has to be fed or rather added by a small dose daily.

 

[rishma]

Baking soda is Sodium Bicarbonate. It does not contain any Calcium or Magnesium. Your coral “eat” or rather consume Ca and Mg so it has to be fed or rather added by a small dose daily.

I don’t agree that magnesium needs to to be added daily. A wide range is acceptable. Adding periodically works fine.

 

[Randy Holmes-Farley]

1.025 salinity. I use a refractometer that I calibrate often.

Red Sea Blue bucket.

I will say I have started dosing Calcium Chloride in "smaller" doses and pulled my calcium back up to 340ish so i feel a lot better and will continue to tinker.

Lost a single hammer head from the colony which made me panic but everything seems alright

Calibrated how?

Even if a sh of 1.025 is accurate, raising salinity to 35 ppt (sg = 1.0264) will boost calcium and magnesium. Magnesium would rise from 1200 to 1267 ppm.

 

[redseanewbie]

Calibrated how?

Even if a sh of 1.025 is accurate, raising salinity to 35 ppt (sg = 1.0264) will boost calcium and magnesium. Magnesium would rise from 1200 to 1267 ppm.

I have Fritz "35ppt calibration fluid" but i call it calibration sauce and i just follow the instructions

 

[Randy Holmes-Farley]

I have Fritz "35ppt calibration fluid" but i call it calibration sauce and i just follow the instructions

I personally would not assume it is accurate, but it might be.

 

[charleydavis]

I don’t agree that magnesium needs to to be added daily. A wide range is acceptable. Adding periodically works fine.

Yes of course. You are correct. I probably should have said periodically.