Magnesium Issue

[Fishreef]

I've been using the API testing but questioned my results. I was referred to the Nyos testing products. I received my magnesium test kit today and it is showing 1530 ppm. I haven't received the Nitrate, calcium or alkalinity kits yet. Im concerned if the magnesium to high. The API kits showed nitrates at 5ppm, alkalinity at 10 and phosphates at 8. I have a 40 gallon aquarium, 7 fish (2 clown, starkie, 2 green chromis, a starry blenny & purpledottyback), 4 coral and 1 purple tip condy anemone.

 

[shwareefer]

I've been using the API testing but questioned my results. I was referred to the Nyos testing products. I received my magnesium test kit today and it is showing 1530 ppm. I haven't received the Nitrate, calcium or alkalinity kits yet. Im concerned if the magnesium to high. The API kits showed nitrates at 5ppm, alkalinity at 10 and phosphates at 8. I have a 40 gallon aquarium, 7 fish (2 clown, starkie, 2 green chromis, a starry blenny & purpledottyback), 4 coral and 1 purple tip condy anemone.

Many people maintain magnesium in the 1500ppm range , so it's not harmful IMO. Since you seem surprised, the question would be how did it get there? Are you dosing magnesium? What salt mix do you use? What is your salinity? All will have an effect on the magnesium concentration.

 

[Randy Holmes-Farley Verified Community Expert]

Whether that value is correct or not, If you haven’t dosed large amounts, magnesium in a new tank will be exactly as it comes in your salt mix and, except in freakishly rare bad batch events, will be fine.

I would not worry about.

 

[Miami Reef]

Whether that value is correct or not, If you haven’t dosed large amounts, magnesium in a new tank will be exactly as it comes in your salt mix and, except in freakishly rare bad batch events, will be fine.

I would not worry about.

How fast does magnesium deplete when compared to calcium?

 

[Fishreef]

Many people maintain magnesium in the 1500ppm range , so it's not harmful IMO. Since you seem surprised, the question would be how did it get there? Are you dosing magnesium? What salt mix do you use? What is your salinity? All will have an effect on the magnesium concentration.

I use Instant Ocean salt and salinity runs 1.027-1.028. I don't dose with anything. I feed frozen brine shrimp alternating with frozen mysis shrimp. I will feed ocean nutrition flakes as a change occasionally.

 

[blaxsun]

How fast does magnesium deplete when compared to calcium?

That really depends. I started out using more magnesium than calcium, but I think it's progressed closer to an even split (probably with the addition of more LPS and SPS). Eventually I think it will probably be more calcium than magnesium.

 

[Randy Holmes-Farley Verified Community Expert]

How fast does magnesium deplete when compared to calcium?

Not more than about 1/10 of the calcium depletion rate, often less, depending on which organisms are involved.

 

[shwareefer]

I use Instant Ocean salt and salinity runs 1.027-1.028. I don't dose with anything. I feed frozen brine shrimp alternating with frozen mysis shrimp. I will feed ocean nutrition flakes as a change occasionally.

Your higher than usual salinity would equate to a higher magnesium level. I'm sure Randy knows the numbers. Most people target 1.025-1.026 salinity.

 

[Miami Reef]

Not more than about 1/10 of the calcium depletion rate, often less, depending on which organisms are involved.

I am assuming stony corals will consume more magnesium than a system like yours, which mainly contained anemones, softies, and LPS.

I can’t wait until you set up another tank. You have outstanding taste in organisms. I need to see a gigantea with a clown trio!

 

[GillMeister]

Mg test kits are fickle and can give you inaccurate results. I use Red Sea test kits and I have to really take my time when testing magnesium levels.

 

[Randy Holmes-Farley Verified Community Expert]

I am assuming stony corals will consume more magnesium than a system like yours, which mainly contained anemones, softies, and LPS.

I can’t wait until you set up another tank. You have outstanding taste in organisms. I need to see a gigantea with a clown trio!

Yes and no. In relation to calcium, coralline is about the biggest user of mag, and the 1/10th comes from known analysis of it. That’s because it deposits high magnesian calcite, while most corals are lower mag/calcium , depositing aragonite.

 

[Miami Reef]

Yes and no. In relation to calcium, coralline is about the biggest user of mag, and the 1/10th comes from known analysis of it. That’s because it deposits high magnesian calcite, while most corals are lower mag/calcium , depositing aragonite.

Slightly off topic, Do you have references that support the idea that algae starts to become limited at 0.03ppm, and having phosphates at 0.10ppm likely won’t have much limiting effect as say, 2.0ppm?

 

[Randy Holmes-Farley Verified Community Expert]

Slightly off topic, Do you have references that support the idea that algae starts to become limited at 0.03ppm, and having phosphates at 0.10ppm likely won’t have much limiting effect as say, 2.0ppm?

I’ve not seen data for the specific pest algae we get in reef tanks, but for phytoplankton there are many studies like this one:

Meta-analysis of the response of marine phytoplankton to nutrient addition and seawater warming - PubMed

As an indispensable part of the marine ecosystem, phytoplankton are important prey for zooplankton and various marine animals with important commercial value. The influence of seawater warming and eutrophication on phytoplankton communities is well known, but few studies have explained the...

pubmed.ncbi.nlm.nih.gov

“Through meta-analysis and meta-regression, the phytoplankton responses to the effects of nutrient addition and seawater warming were evaluated in this study. Nitrogen (N) addition led to an increase in phytoplankton biomass, while phosphorus (P) had no significant effect on phytoplankton biomass. However, this result may be biased by the uneven distribution of the research area. N limitation is widespread in the areas where these collected studies were conducted, including many parts of North and South Atlantic and West Pacific Oceans. The key limiting nutrient in other areas lacking corresponding experiments, however, remain unclear.”

 

[Randy Holmes-Farley Verified Community Expert]

Also check this one:

Wayback Machine

 

[Miami Reef]

@Randy Holmes-Farley

I just wrote this article. I’d really be honored for your review on it. https://www.reef2reef.com/threads/the-misconception-of-algae-nutrients-a-solution-article.907489/

 

[Fishreef]

Your higher than usual salinity would equate to a higher magnesium level. I'm sure Randy knows the numbers. Most people target 1.025-1.026 salinity.

My lfs told me to run it at 1.027 - 1.028 because of the invertebrates. So I need to lower the salinity? I've had my aquarium for almost 4 years. I'm always open to information to help me. Thanks

 

[shwareefer]

My lfs told me to run it at 1.027 - 1.028 because of the invertebrates. So I need to lower the salinity? I've had my aquarium for almost 4 years. I'm always open to information to help me. Thanks

I've never heard of that, but that doesn't mean it's not a thing. Kind of wierd to recommend being more salty than the actual ocean, however less salty gets recommended all the time so who knows. Even the saltiest part of the Atlantic is 1.0268. Maybe someone else will chime in.

 

[Randy Holmes-Farley Verified Community Expert]

I do not think it’s a thing. lol

35 ppt is plenty high for any normal marine organism.

 

[Fishreef]

I do not think it’s a thing. lol

35 ppt is plenty high for any normal marine organism.

I'm glad I have a forum to turn too. I've been mislead so much. Thank you all

 

[Randy Holmes-Farley Verified Community Expert]

I'm glad I have a forum to turn too. I've been mislead so much. Thank you all

You're welcome.

Happy Reefing!