Magnesium level after aqua forest component pro 3 question

[n8harp]

My magnesium level was 1140 around noon. I haven’t dosed magnesium basically ever for my tank, but I’d like to get it up to around 1250 which is what my salt mix is at.

I dosed aquaforest component pro 3 and 2 hours later my magnesium was 1215. I am fine with this, but the label for the product says the amount I added (25mL) will raise magnesium by only 0.75 ppm. This can’t be right? Or am I missing something. The amount of component pro I would have had to raise the magnesium that much would be astronomical. Are magnesium test kits that poor and flawed? It’s a salifert one

 

[Randy Holmes-Farley Verified Community Expert]

Magnesium testing is so frequently inaccurate that I do not recommend it.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

 

[n8harp]

Ahh thank you sir, that is a really helpful article.


My tank uses about 7–9 ppm of calcium per day. It’s a 26g cube with 2 acans (around 8 heads each), 5 bubble tip anemones, two montis (one red, one encrusting, not sure on exact ID), one unidentified SPS, and a few weeks ago I added 2 birds nest frags, a hammer frag, and then last weekend two acropora frags. I’ve also got a few mushrooms and a kenya tree (I am upgrading my tank to a UNS R90 in the coming months). Most things are still frag sized, but the anemones are getting pretty big and now take up about ¼ of the rockwork. I am also dealing with aiptasia outbreak.


I’m still dialing in nutrient and dosing demand. I attached an Excel tracker, I only recently started tracking things properly. Before that I was kind of dosing by feel, and when I finally checked alkalinity it was below 6, which was a wake-up call.


Alk is much more stable now, usually 7.3–8.3 dKH but I would like to keep it 7.7-8.3. I’m dosing Seachem Reef Fusion 2 for alk and Seachem Reef Complete for calcium. I hadn’t been dosing magnesium until today.


Should I follow your recommendation of ~1 ppm magnesium for every 10 ppm calcium dosed? I do have AquaForest Pro Components, but I haven’t started using them yet other than the magnesium today. Once I switch over I know I’ll need to re-dial things in and how much to dose with the component pro additives, but dosing magnesium relative to calcium sounds way easier.

My alkalinity seems to drop about 1 dKH per day. I have not tested consistently in terms of time of day so I am still working on understanding exactly how much is being consumed daily. My pH this morning was about 7.9 and salinity is rocking at 34.6.

Thanks again for the article

 

[n8harp]

Actually I probably should not dose the component pro 3 magnesium as my current calcium supplement says it maintains magnesium. So I guess I should hold off on the component pro 3 until I switch to the full system component pro 1,2,3. Perhaps an ICP test is in order just to see where everything is at exactly

 

[n8harp]

Edit, my alkalinity only drops by about 0.5 dKH a day looking at the excel file.

 

[Randy Holmes-Farley Verified Community Expert]

Actually I probably should not dose the component pro 3 magnesium as my current calcium supplement says it maintains magnesium.

What is that calcium supplement?

A test of your salt mix and comparison to your tank can sometimes be a helpful gauge as to whether the tank is low enough to warrant anything above the RMM amounts.

 

[n8harp]

Salt mix is aquaforest reef salt. I tested my current batch at
35ppt
Alk: 8.0
Calcium: 420
Magnesium: doesn’t matter bc I think it tests low. Said 1260 but tested same salt at 1210 so… the manufacturer says it’s ICP tested above 1340 I believe between that and 1450 or something

Calcium dropped from 420 to 400 from 5:30pm yesterday until 11am today.

I dosed 4 mL of reef fusion 2 (raises carbonate alkalinity) last night around 10pm. Bottle states it contributes 0.176 meq/L for every 1mL solution in 25L of water and my tank is 100L. My alkalinity was 7.7 last night a bit after photo period around 10pm, dosed 4 mL and at 11am it was 8.0 dKH

 

[Randy Holmes-Farley Verified Community Expert]

The Reef Complete adds mag at 5% of calcium if you believe Seachem. That is in the 5-10% range I suggest for RMM.

Calcium testing is too variable to adjust the dose every day. Base it off alk dosing, or dose every day and only change it based on many calcium tests over time.

 

[shadynate]

How frequently would you test calcium when trying to understand how much your tank is up taking?

 

[Randy Holmes-Farley Verified Community Expert]

How frequently would you test calcium when trying to understand how much your tank is up taking?

I wouldn’t. I would calculate the calcium drop based on the alk drop.

But if I was to use calcium, how often depends on the demand, but maybe after 3-10 days so the drop is substantial and not just testing noise.