HELP! Dosing Red Sea Magnesium

[G’sReef]

Hello fellow reefers, am getting ready to dose my DT for the first time. I just trying to make sure am reading this correctly. My tank is about 125 gallons and my Magnesium is at 1240ppm….,according to the dosing instructions it says I need to dose 550ml! That just sounds like a lot, am I reading this incorrectly?? Thanks in Advance!

 

[blaxsun]

Assuming this is the liquid supplement, 5ml will raise your magnesium by 1ppm - so 50ml would raise it by 10ppm and 500ml would raise it by 100ppm, so yeah - if you're aiming for 1350ppm you'd need to add 550ml. But...

There is a maximum daily amount no greater than 10ppm (50ml in your case), so you'd need to dose this over the next 11 days (or longer).

You might find this link useful.

https://www.redseafish.com/wp-content/uploads/2020/11/24783_Manual-Foundation-Supplements_GB-DE-FR-NL-SP_v21c-WEB.pdf

 

[G’sReef]

Awesome! Thanks for your help.

 

[Randy Holmes-Farley Verified Community Expert]

IMO, that is unnecessarily slow. It can easily be raised faster than that if you use a quality product.

That said, low magnesium most often is either test error or low salinity. Even a small boost to salinity boosts magnesium a lot. sg from 1.025 to 1.026 boosts magnesium in NSW from 1212 ppm to 1260 ppm.

What is the salinity and how is is measured

 

[blaxsun]

IMO, that is unnecessarily slow. It can easily be raised faster than that if you use a quality product.

I'm sure that's the case, but I always prefer to err on the side of caution (at least when it's not my tank anyway). I didn't realize there was a correlation between salinity and magnesium - thanks for the tip!

 

[nereefpat]

My tank is about 125 gallons and my Magnesium is at 1240ppm

1240 ppm is absolutely fine. Why do you want it higher?

I didn't realize there was a correlation between salinity and magnesium - thanks for the tip!

It's just because salt mixes contain Mg. So if salinity is 10% low, for example, Mg would be 10% lower than full strength.

 

[G’sReef]

I use a refractometer to measure my salinity which is at about 1.026. All my parameters are low(Ca@370,[email protected],Mg@1240) and I believe this is cause I haven’t been concerned which cause I have a fish only system right now. I am preparing for corals so am trying to get my levels were they need to be.

 

[G’sReef]

1240 ppm is absolutely fine. Why do you want it higher?


It's just because salt mixes contain Mg. So if salinity is 10% low, for example, Mg would be 10% lower than full strength.

Red Sea wants it at 1350 for a mixed reef.

 

[nereefpat]

I use a refractometer to measure my salinity which is at about 1.026.

Have you recently calibrated it with a saltwater standard?

Red Sea wants it at 1350 for a mixed reef.

That would higher than natural seawater, but many folks do keep it that high.

 

[Just a Wrasse.]

Your magnesium seems fine.

 

[G’sReef]

Have you recently calibrated it with a saltwater standard?

That would higher than natural seawater, but many folks do keep it that high.

Whats a saltwater standard? I thought you calibrated it by using RO water and making sure it’s at zero. I kinda double check after mixing salt water and it measures correctly.

 

[G’sReef]

Your magnesium seems fine.

I guess if you wanna stick to the Red Sea recipe it suppose to be at 1350.

 

[nereefpat]

Whats a saltwater standard? I thought you calibrated it by using RO water and making sure it’s at zero. I kinda double check after mixing salt water and it measures correctly.

There are commercial calibration fluids available. Or you can make your own with a scale, table salt, and RO water.

I would not trust a refractometer that is calibrated with RO water, unless you check it with a standard after calibration.

 

[G’sReef]

Ok. Where can I get this calibration fluid?

 

[nereefpat]

Ok. Where can I get this calibration fluid?

Here's one: https://www.bulkreefsupply.com/pinpoint-salinity-calibration-fluid.html

There are others. Just Google.

Or, you can make your own, as Randy Discusses here: https://www.reef2reef.com/threads/diy-salinity-calibration-solutions.220052/ . The short version is that 36.5 grams of table salt in a total of 1 liter of RO water will read 35 ppt on a refractometer.

 

[G’sReef]

Thanks!

 

[Drewbacca]

Whats a saltwater standard? I thought you calibrated it by using RO water and making sure it’s at zero. I kinda double check after mixing salt water and it measures correctly.

Fyi.. for anyone coming accross this..since i dont think the reason was given..
If you are calibrating something so you get accurate readings.. you want to calibrate it with something as close to what you want your reading to be.. vs. Zero which gives lots of room for drift or error since its accurate at zero now.. not necessarily up at 35. Its like a spring scale being calibrated at zero while you way 225 lb. It would be way better to sit 2 hundred lb.s of weight plates on it and calibrate it there.. who cares if when nothing is on it its not right at zero... you care if when 2hundred is on it.. it says 2hundred. (Sorry for spelling it out.. dropped my phone and its cracked right where the # zero is. Lol)

 

[saltlyfe]

Assuming this is the liquid supplement, 5ml will raise your magnesium by 1ppm - so 50ml would raise it by 10ppm and 500ml would raise it by 100ppm, so yeah - if you're aiming for 1350ppm you'd need to add 550ml. But...

There is a maximum daily amount no greater than 10ppm (50ml in your case), so you'd need to dose this over the next 11 days (or longer).

You might find this link useful.

https://www.redseafish.com/wp-content/uploads/2020/11/24783_Manual-Foundation-Supplements_GB-DE-FR-NL-SP_v21c-WEB.pdf

Okay, so I'm pretty new to this and trying to calculate for a 50 gallon tank. Does this mean it will take 2ml to raise 1ppm in my tank. Would my max daily be 20ML of magnesium? I don't know if my math is mathing right now :/

 

[nereefpat]

Okay, so I'm pretty new to this and trying to calculate for a 50 gallon tank. Does this mean it will take 2ml to raise 1ppm in my tank. Would my max daily be 20ML of magnesium? I don't know if my math is mathing right now :/

What product are you using?

 

[cspo15]

What product are you using?

I am stuck on the same thing but I have a 25 gal tank. I am trying to add magnesium but want to get it right. In my case, I’m using the Red Sea Mag C. So according to the instructions I would need to add over 210 ml (being that my mag levels are currently 1080) to get it up to around 1350 for a mixed reef tank? Is this something that I have to add over time and not all at once? Thanks