BRS 2 part Magnesium, how much do I dose?

[FugeTown]

What's up Reef2reef ,
My tank has become a Magnesium consuming machine since I've been adding many more lps corals to my 40 Gallon breeder. I used to use Fluval Sea 8 oz bottle Magnesium but now with a higher demand it's a waste of money. I just purchased Bulkreefsupply's 2 part magnesium and this is all the instructions say

One bag mixes with water to create a gallon of solution.


This mix of magnesium chloride and sulfate is designed to be used in conjunction with the two part dosing system as part of standard parameter maintenance.


Maintaining proper magnesium levels will help prevent calcium and alkalinity from precipitating which makes maintaining these levels easier as well.

Is any body familiar with exactly how many ml of this stuff I should use? I have been dosing 10ml of the Fluval sea a day which kept my Magnesium steady at 1320.

 

[sbash]

I do not know anything about this product, but in my dosing experience; it is completely variable on each system. Start with a low dose (say, 1 or 2ml), and adjust accordingly...

 

[klesel]

Brs has a video showing you how to dose the 2 part includes the mag how to

 

[Potatohead]

https://www.bulkreefsupply.com/reef-calculator/

 

[FugeTown]

Brs has a video showing you how to dose the 2 part includes the mag how to

Just found the video , they should include in the instructions that there's a calculator on the brs website for noobs like me lol thanks for your help.

 

[Randy Holmes-Farley Verified Community Expert]

Is any body familiar with exactly how many ml of this stuff I should use? I have been dosing 10ml of the Fluval sea a day which kept my Magnesium steady at 1320.

Yes, I designed this system.

Are you using the other parts of the two part? If so, you dose the equivalent of 610 mL of the magnesium solution over the time you dose 1 full gallon of the alkalinity part.

 

[FugeTown]

Yes, I designed this system.

Are you using the other parts of the two part? If so, you dose the equivalent of 610 mL of the magnesium solution over the time you dose 1 full gallon of the alkalinity part.

It's a premixed 2 part containing Magnesium chloride and Magnesium sulfate that makes a gallon jug of solution for 10.99 free shipping which was a good deal. I found the Magnesium calculator on BRS website and my magnesium was where I wanted it at 1320 but I was so curious to how accurate the calculator was so I typed in my gallons and mag level and put desired Magnesium level at 1360 then it said to add 3 oz of the gallon jug formula which I did and sure enough after I tested again with salifert my level rose to 1360. This stuff sure beats that little container you buy at petco for 15.99.

 

[Randy Holmes-Farley Verified Community Expert]

It's a premixed 2 part containing Magnesium chloride and Magnesium sulfate that makes a gallon jug of solution for 10.99 free shipping which was a good deal. I found the Magnesium calculator on BRS website and my magnesium was where I wanted it at 1320 but I was so curious to how accurate the calculator was so I typed in my gallons and mag level and put desired Magnesium level at 1360 then it said to add 3 oz of the gallon jug formula which I did and sure enough after I tested again with salifert my level rose to 1360. This stuff sure beats that little container you buy at petco for 15.99.

I'm glad you like it.

In general, I'd dose it based on the recommended recipe and not the magnesium level (unless it is already too high) because it adds more than just magnesium (the sulfate is important too), and dosing as recommended will keep the magnesium more stable than waiting until it gets out of whack and dosing a bunch.

 

[FugeTown]

I'm glad you like it.

In general, I'd dose it based on the recommended recipe and not the magnesium level (unless it is already too high) because it adds more than just magnesium (the sulfate is important too), and dosing as recommended will keep the magnesium more stable than waiting until it gets out of whack and dosing a bunch.

My tank is funny maybe cause my only SPS corals are 3 little birdsnest frags but most of my corals are lps , softies & polyps so probably explains why my calcium level drops really slow. I do dose alkalinity every day to maintain it at 10dkh my magnesium drops consistently ever since I added my huge maze coral and flowerpot coral. This is why I only dose the Magnesium by itself because the calcium would be sky rocket high if I had a solution with everything in it.

 

[Randy Holmes-Farley Verified Community Expert]

My tank is funny maybe cause my only SPS corals are 3 little birdsnest frags but most of my corals are lps , softies & polyps so probably explains why my calcium level drops really slow. I do dose alkalinity every day to maintain it at 10dkh my magnesium drops consistently ever since I added my huge maze coral and flowerpot coral. This is why I only dose the Magnesium by itself because the calcium would be sky rocket high if I had a solution with everything in it.

You cannot actually be consuming more magnesium than calcium.

The usual ratio of consumption for each 1 meq/L (2.8 dKH) 0f of alkalinity is about 18-20 ppm calcium and 0-2 ppm magnesium.

If you are finding a much bigger apparent demand for magnesium, that can only be because water changes with a mix that does not match the tank are messing with the ratios. (or test error, which is very common for magnesium)

If that is the case, boosting the new salt mix may eliminate these concerns.

 

[FugeTown]

Read this post you replied to a long time ago it clearly says some corals and coralline algae can consume more Magnesium than others , what's the deal with that now lol
I have my salifert Magnesium test kit procedure down for sure. Actually my magnesium would drop really slow before I added the new corals. I used to test my magnesium once a week now I'm keeping a closer eye on it but since I've been dosing it daily the numbers seemed to stable out better but still drops faster than the calcium. Here's your older post

Are you doing water changes? What salt?

Some reactor media is deficient in magnesium, and people sometimes add some dolomite to the reactor for that reason.

FWIW, the magnesium to calcium ratio is likely the same for a given coral as it grows. But some corals and especially coralline algae consume more magnesium than others.





__________________
Randy Holmes-Farley

Current Tank Info: 120 mixed reef

So after reading this it seems possible for Magnesium to drop at a faster rate than calcium , correct?

 

[Randy Holmes-Farley Verified Community Expert]

Read this post you replied to a long time ago it clearly says some corals and coralline algae can consume more Magnesium than others , what's the deal with that now lol

...


So after reading this it seems possible for Magnesium to drop at a faster rate than calcium , correct?

lol No.

The variable magnesium incorporation is why, for each 2.8 dKH of alkalinity, calcium incorporation is 18-20 ppm and magnesium incorporation is 0-2 ppm.

There is no significant sink for magnesium on its own in a normal reef tank.

 

[FugeTown]

lol No.

The variable magnesium incorporation is why, for each 2.8 dKH of alkalinity, calcium incorporation is 18-20 ppm and magnesium incorporation is 0-2 ppm.

There is no significant sink for magnesium on its own in a normal reef tank.

Guess I'm learning new stuff today
My alkalinity drops 1 dkh per day
Calcium drops about 10 ppm a week maybe less
And Magnesium drops about 10 ppm a day
With your formula my magnesium should be dropping only.5 a day at my dkh drop rate of 1 dkh a day and calcium "should" be dropping 6 ppm a day so guess my reef tank isn't normal.
Am I not dosing enough dkh or something? Is keeping it at 9.6 dkh too low for the calcium to drop at your normal reef tank rate mentioned above? my calcium is at 420 salinity is 35ppt temp is 78, Magnesium is 1360 dkh 9.6. Help me out buddy what do you thinks the reason the calcium is not dropping that fast?

 

[Randy Holmes-Farley Verified Community Expert]

Guess I'm learning new stuff today
My alkalinity drops 1 dkh per day
Calcium drops about 10 ppm a week maybe less
And Magnesium drops about 10 ppm a day
With your formula my magnesium should be dropping only.5 a day at my dkh drop rate of 1 dkh a day and calcium "should" be dropping 6 ppm a day so guess my reef tank isn't normal.
Am I not dosing enough dkh or something? Is keeping it at 9.6 dkh too low for the calcium to drop at your normal reef tank rate mentioned above? my calcium is at 420 salinity is 35ppt temp is 78, Magnesium is 1360 dkh 9.6. Help me out buddy what do you thinks the reason the calcium is not dropping that fast?

No, your tank consumption is nothing miraculous.

This is not rocket science.

The calcium and alkalinity are close enough that test error easily explains the difference between 18-20 ppm calcium for each 2.8 dKH and your observed 28 ppm calcium per 2.8 dKH. There's no POSSIBLE sink for more calcium than 20 ppm per 2.8 dKH of alkalinity (pure calcium carbonate).

Water changes messing with ratios, and/or test error must explain what you observed for both calcium and magnesium having higher demand than explainable by alk declines.

What salt mix?

If you are dosing nitrate, that is adding a small amount of alkalinity when it is metabolized which will have a small effect on the alk in the tank.

 

[FugeTown]

No, your tank consumption is nothing miraculous.

This is not rocket science.

The calcium and alkalinity are close enough that test error easily explains the difference between 18-20 ppm calcium for each 2.8 dKH and your observed 28 ppm calcium per 2.8 dKH. There's no POSSIBLE sink for more calcium than 20 ppm per 2.8 dKH of alkalinity (pure calcium carbonate).

Water changes messing with ratios, and/or test error must explain what you observed for both calcium and magnesium having higher demand than explainable by alk declines.

What salt mix?

If you are dosing nitrate, that is adding a small amount of alkalinity when it is metabolized which will have a small effect on the alk in the tank.

I only do water changes once a month , I'm trying to just keep my "big 3" dkh, calc, mag at the correct levels by dosing when needed . For example when my calcium drops to 400 I usually dose Kents liquid calcium raising it around 20 ppm and I dose fusion alkalinity formula 1tsp after I dose the calcium. My calcium usually stays up for a good week to three weeks above 400 but I still keep dosing the fusion 1 tsp a day every morning to keep my alkalinity stable. I test my magnesium to and add it when it's needed.
When I do my water changes I use instant oceans reef crystals.

 

[Randy Holmes-Farley Verified Community Expert]

How do you "know" your magnesium demand is 10 ppm per day?

You said 10 mL of Fluval magnesium maintained it? For how long? What is your tank volume?

 

[FugeTown]

How do you "know" your magnesium demand is 10 ppm per day?

You said 10 mL of Fluval magnesium maintained it? For how long? What is your tank volume?

I was testing my magnesium everyday for two weeks. The first few days it dropped like a ghetto gangsters pants while walking in public(about -40 ppm p/day) which I kept dosing 20 ml of the mg a day to bring it back up above 1300 after that it would drop roughly around 10 - 20 ppm consistently for 10 days straight. My tank volume is 40 gallons.

 

[Randy Holmes-Farley Verified Community Expert]

I'll just say I'm quite certain the 40 ppm per day was purely testing error. I've had people say just the opposite, with it rising 50 ppm overnight, which it can't do either (without dosing).

 

[FugeTown]

I'll just say I'm quite certain the 40 ppm per day was purely testing error. I've had people say just the opposite, with it rising 50 ppm overnight, which it can't do either (without dosing).

I'm gonna take that into consideration and perform 3 consecutive Magnesium tests tomorrow and see if they all come back with the same results. I never researched the reviews on the salifert Magnesium test kit so maybe it's inconsistent but the preciseness of the kits instruments makes it seem unlikely for inaccuracies.

 

[Randy Holmes-Farley Verified Community Expert]

The Red Sea is the one that gives people the most trouble:

Big 3 Shootout Alk, Ca, Mg: RedSea, Nyos, Elos, Salifert, API, Hanna, Triton, AWT
https://www.reef2reef.com/threads/b...os-elos-salifert-api-hanna-triton-awt.234660/

Magnesium:
Red Sea: 2080
Elos: 1350
Nyos: 1440
Salifert: 1470
AWT A: 1540
AWT B: 1560
Triton A: 1475
Triton B: 1468