Need some help with Magnesium!

[drainbamage]

So I've learned how important magnesium is- but now I'm looking for clarification on a few things in terms of dosing it.


Epsom salt is Magnesium Sulfate MgSO4·7H2O - so when it breaks down into the tank, I'm assuming you get - MgSO4·7H2O -> Mg + SO4 + H20(excess) or does the breakdown occur some other way? If this is the case, what are the risks of having those sulfate's cruising around? Essentially this means you're dosing the tank with Sulfur, right? Any ups or downs with this?



Now BRS recommends doing Magnesium Sulfate along with Magnesium Chloride- And their claim is that the sulfate and chloride balances out somehow- is the reaction then:
MgSO4·7H2O + MgCl2(H2O)x -> Mg + SO4Cl2 + H2O(excess) ??

So is the Sulfur Chloride a stable ion(??) or somehow less 'bad' for the tank than the free sulfur? I know Brightwell's Magnesium supplement is a blend of the two magnesium's as well, so I'm guessing there must be a reason, I'd just like to see if we could figure out the actual reason instead of just assuming.

Thanks in advance all!!

 

[Lateral72]

Sulfate is the 3rd most common ionic compound in Seawater. It's completely different than elemental Sulfur.

 

[drainbamage]

Sulfate is the 3rd most common ionic compound in Seawater. It's completely different than elemental Sulfur.

So will adding the extra sulfate cause any issues? Or is there any potential for the sulfate to decompose if in levels of excess elevation?

 

[OMG Corals]

You should see no detrimental effects from the sulfates. If any thing it would be broken down through biological process as sulfides or sulfer gases, and removed by the skimmer, water changes, or given off at the surface in exchange.

 

[drainbamage]

You should see no detrimental effects from the sulfates. If any thing it would be broken down through biological process as sulfides or sulfer gases, and removed by the skimmer, water changes, or given off at the surface in exchange.

These links:

Aquarium Chemistry: A Homemade Two-Part Calcium And Alkalinity Additive System — Advanced Aquarist's Online Magazine

Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

both state that the sulfates won't break down, and only water changes will reduce the build-up via dilution. Neither suggest however (that I found in my reading) what the directly harmful effects of the elevated sulfates would be- both simply suggest it's a bad thing :squigglemouth:

The RK article also states though that elevating the magnesium beyond 30ppm using an epsom salt solution is definitely a bad idea- but again doesn't really give details except to suggest the overall salinity will be raised :squigglemouth: :squigglemouth:

Any more thoughts all??

 

[_Alex_]

Guy from my local club has used Epson salt for years and had no ill effects from it. I was thinking about trying it bit regular water changes keeps mine spot on in the 40b.

 

[nixer]

perhaps this might help http://reefkeeping.com/issues/2005-12/rhf/index.php

 

[VegasRick]

As far as I know there has never been any proof that long term use of Epsom Salt and thereby changing the ratio however slight it might be leads to problems. The general consensus is to keep it as close to NSW levels as possible because what would happen is not really known. I believe it was Martin Moe who said the ions in seawater are like a big square dance, constantly moving and changing partners. Better to stick with NSW levels than to take chances with unknown consequences.

Another article perhaps more relative to your quest where the author touches upon it.
What is Seawater? by Randy Holmes-Farley - Reefkeeping.com

Now all that being said if you are using a salt with high Mg levels and only trying to maintain NSW of Magnesium, then you wont be adding a whole lot of Magnesium Sulfate to your system and regular water changes should keep it from being too skewed . If on the other hand your goal is un-naturally high Mg levels as seems to be a trend you will end up adding significant amounts of it to your tank. If that is your goal then I would definitely choose a balanced approach of a proper ratio of chloride to sulfide. I personally use a balanced approach even though I may only adjust my Mg levels every 3 months or so.

FWIW Magnesium levels have changed through time. The ratio of Mg uptake in coral skeleton is proportional to the levels in the water at the time. This leads me to believe that corals are not actively seeking the Mg.

 

[OMG Corals]

These links:

Aquarium Chemistry: A Homemade Two-Part Calcium And Alkalinity Additive System — Advanced Aquarist's Online Magazine

Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

both state that the sulfates won't break down, and only water changes will reduce the build-up via dilution. Neither suggest however (that I found in my reading) what the directly harmful effects of the elevated sulfates would be- both simply suggest it's a bad thing :squigglemouth:

The RK article also states though that elevating the magnesium beyond 30ppm using an epsom salt solution is definitely a bad idea- but again doesn't really give details except to suggest the overall salinity will be raised :squigglemouth: :squigglemouth:

Any more thoughts all??

Not wanting to start a huge rant here or argue, but niether say that the build up of sulfate are "bad". Only that it may bring the levels above NSW. However sulfates can be broken down through biological process as sulfides in hydrogen sulfide. It is then given off as a gas. This can occur in the sandbed (if you have one) or deep within the live rock. Anerobic bacteria will fixate on sulfate and sulfides in the water and break it down into gases. These gases are slowly released and given off or dissoluted and skimmed or removed with water changes.

Also, Phytoplankton will convert the sulfates to dimethylsulfide. Which may not fully occur in aquaria, but i think it's an interesting fact and would be a fantastic way to use the excess.

The reason the levels will rise is that this biological process is not always as previlent in aquaria and we add more than the bacteria can break down. Sulfate is found in a concentration of about 2700ppm in NSW. So, i would think that anything in that target area would be fine. I could see an elevated level being a problem only if it is broken down too quickly and elevated hydrogen sulfide or dimethylsulfide are produced. This as we all know would be bad as these gases are toxic in high concentration.

I am curious if biopellets would be capable of this breakdown. It would be an interesting thing to research. If they do, the excess could be skimmed off when released from the reaction chamber.

 

[OMG Corals]

I forgot to add, that depending on the amount you need to raise the mag, Epson salts may not be the best choice. If you need to go up alot, you may want to use a magnesium chloride suplement. Such as a mag flake product or something similar.

Sorry to hijack the thread a little. I'm just kinda a chemistry geek:nerd: I find it very interesting.

 

[OMG Corals]

Sulfur reactors and the addition of sulfur cause an oxidation effect that would convert nitrate into nitrogen gas. So I would think that this would occur also. See the Reef Aquarium vol 3 page 286.

 

[drainbamage]

Guy from my local club has used Epson salt for years and had no ill effects from it. I was thinking about trying it bit regular water changes keeps mine spot on in the 40b.

Any idea how much of it he's been using? All the articles I found suggested that it would take a long time before ill-effects would be seen, and/or if adding the epsom salts in high levels.

perhaps this might help Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

Thanks Nixer! Going to give this one a read, but oh my, it'll have to be done with a glass of whiskey for lubrication :xd:

As far as I know there has never been any proof that long term use of Epsom Salt and thereby changing the ratio however slight it might be leads to problems. The general consensus is to keep it as close to NSW levels as possible because what would happen is not really known. I believe it was Martin Moe who said the ions in seawater are like a big square dance, constantly moving and changing partners. Better to stick with NSW levels than to take chances with unknown consequences.

Another article perhaps more relative to your quest where the author touches upon it.
What is Seawater? by Randy Holmes-Farley - Reefkeeping.com

Now all that being said if you are using a salt with high Mg levels and only trying to maintain NSW of Magnesium, then you wont be adding a whole lot of Magnesium Sulfate to your system and regular water changes should keep it from being too skewed . If on the other hand your goal is un-naturally high Mg levels as seems to be a trend you will end up adding significant amounts of it to your tank. If that is your goal then I would definitely choose a balanced approach of a proper ratio of chloride to sulfide. I personally use a balanced approach even though I may only adjust my Mg levels every 3 months or so.

FWIW Magnesium levels have changed through time. The ratio of Mg uptake in coral skeleton is proportional to the levels in the water at the time. This leads me to believe that corals are not actively seeking the Mg.

This is what the research I found suggested as well- that small variations weren't that big of a deal, but large variations (adding greater than 30~50ppm increases) would be a problem- but none suggested exactly why or what problems would arise.

Part of the reason i'm asking this is for my own use- I currently use the BRS 3 part system with the 2 part mag mix, but here in San Diego, we have NSW available from our local coast (Scripps institute of oceanography provides sand-filtered ocean water.) One of the oddities though is the water is extremely stripped of magnesium, less than 1000ppm regularly. To bring it up to 'tropical' levels of NSW, there's a need to add a significant amount of mag suppliment.

 

[drainbamage]

I forgot to add, that depending on the amount you need to raise the mag, Epson salts may not be the best choice. If you need to go up alot, you may want to use a magnesium chloride suplement. Such as a mag flake product or something similar.

Sorry to hijack the thread a little. I'm just kinda a chemistry geek:nerd: I find it very interesting.

Hey- no need to apologize one bit! I like the chemistry answer- I'm no pro on chemistry info, but I'd rather learn the nitty gritty answer than the " so you can think of it as like when you bake a cake" answer.

And yea- none of the links I found outwardly stated that the high level of sulfates were bad, rather they suggested (as I said :angel that elevated levels were to be avoided by saying "don't add epsom salt beyond needs to raise 30ppm magnesium." So now I'm trying to figure out what elevated sulfates would be detrimental to, and at what point it would become detrimental to the tank. As I said above, I'm researching this for a situation where the water would need over 300~400PPM mag increase.

In such a case, would the idea of adding mag sulfate and mag chloride create a binding of the sulfates and chlorides? Or rather are the two left as free ions, but merely 'balance' out each other to prevent excess levels of either in relation to the other?


Thanks for all the answers so far everyone!! If I'm seeming to disagree or discard your advice, I'm noT!!! I'm just trying to find as detailed of an answer as possible.

 

[drainbamage]

any more thoughts guys? Sorta need to figure out what the risk/damage is of raising mag levels by over 100ppm using Epsom salts, or what the advantage is of using the mixed Mag solution