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It is the way it is!!!!
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Discussion Starter · #1 ·
I am toying with the idea of dosing my tank with Epsoms Salt to bring the Mg. up to around 1400, my question is will this have an effect on my salinity?

My parameters as of right now are:

Cal. 465
Alk. 4 meg/l
Mg. 1250

I test with Seachem test kits and will change to Salifert next time I need to buy them again. Does 1400 sound like where I need to be with the Mg. I plan on bringing the Cal. to 480 and the Alk. to 4.5 meg/l. Please tell me if I am on the right track or if I need to be doing something different. I have various LPS and few SPS but I do have 2 clams that are 6 plus inches in size and 1 -3 inch clam, and will probably add a couple more medium ones in the future. Thanks, Joe
 

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Im not sure, dont add this to your tank until you hear from some of the pros here,

but if you did it has to be done very very slowly and in small ammounts at a time.
 

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c.a.g. owner and operator
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i honestly see no reason to keep the levels any higher than natural sea water . 6.5 meq/l will propably kill everything in your tank ! thats a dkh reading higher than 16 ! even at 4 meq/l you are pushing it as that puts you somewhere around 11 dkh . to answer your question about your salinity rising with the mag addition , you probably won't be adding enough but to only slightly raise it in a 120. but again i would have to ask why? 1250 is plenty .
 

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c.a.g. owner and operator
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again , (please don't take this as i'm beating up on you ) but what are you tring to accomplish by keeping the values so high ? a dkh of 7-8 , a value of 380 p.p.m. of calcium , and a value of 1200 p.p.m. of magnesium will support everything in your tank . remember the higher you push the values the more work you will have to do to keep them there . i for one don't like to spend a lot of time trying to figure it out .
 

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It is the way it is!!!!
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Discussion Starter · #6 ·
:lol: Im used to taking a beating, No just kidding, thats what I am looking for, constructive critisism. My reasoning is that it just seems like all that I have read and heard that with clams you need to keep your values a little higher, but if this is not the case then I am game to do what is right. I am trying to get everything on a schedule and I just want to know the correct parameters to keep everything at.
 

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c.a.g. owner and operator
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well if its constructive critisism your looking for , then .......
the only reason i could see to have elavated values would be if you are running a deep sand bed ,as that will use more alk & calcium than your current corals and clams . even then i would run my tank at maybe 9 dkh and 420 or so on the calcium . again i think that you will find it much easier to maintain these levels than those crazy levels others keep .
hey, i know when you see some of those great looking italian tanks that use the crazy levels they use , its hard not wanting to follow their method ! i pondered about it myself , but others here kept me straight .
 

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It is the way it is!!!!
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Discussion Starter · #8 ·
Thanks for your replies Gwaco. Now another ? How do you convert DKH to Meg/L?
 

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How do you convert DKH to Meg/L?
ignore the first row and slide the headings over........

<TABLE cellSpacing=0 cellPadding=2 width=620 border=1><TBODY><TR><TD>KH value in dKH</TD><TD>Alkalinity in meq/L</TD></TR><TR><TD>0.00</TD><TD>16.0</TD><TD>5.71</TD></TR><TR><TD>0.02</TD><TD>15.7</TD><TD>5.60</TD></TR><TR><TD>0.04</TD><TD>15.4</TD><TD>5.49</TD></TR><TR><TD>0.06</TD><TD>15.0</TD><TD>5.37</TD></TR><TR><TD>0.08</TD><TD>14.7</TD><TD>5.26</TD></TR><TR><TD>0.10</TD><TD>14.4</TD><TD>5.14</TD></TR><TR><TD>0.12</TD><TD>14.1</TD><TD>5.03</TD></TR><TR><TD>0.14</TD><TD>13.8</TD><TD>4.91</TD></TR><TR><TD>0.16</TD><TD>13.4</TD><TD>4.80</TD></TR><TR><TD>0.18</TD><TD>13.1</TD><TD>4.69</TD></TR><TR><TD>0.20</TD><TD>12.8</TD><TD>4.57</TD></TR><TR><TD>0.22</TD><TD>12.5</TD><TD>4.46</TD></TR><TR><TD>0.24</TD><TD>12.2</TD><TD>4.34</TD></TR><TR><TD>0.26</TD><TD>11.8</TD><TD>4.23</TD></TR><TR><TD>0.28</TD><TD>11.5</TD><TD>4.11</TD></TR><TR><TD>0.30</TD><TD>11.2</TD><TD>4.00</TD></TR><TR><TD>0.32</TD><TD>10.9</TD><TD>3.89</TD></TR><TR><TD>0.34</TD><TD>10.6</TD><TD>3.77</TD></TR><TR><TD>0.36</TD><TD>10.2</TD><TD>3.66</TD></TR><TR><TD>0.38</TD><TD>9.9</TD><TD>3.54</TD></TR><TR><TD>0.40</TD><TD>9.6</TD><TD>3.43</TD></TR><TR><TD>0.42</TD><TD>9.3</TD><TD>3.31</TD></TR><TR><TD>0.44</TD><TD>9.0</TD><TD>3.20</TD></TR><TR><TD>0.46</TD><TD>8.6</TD><TD>3.09</TD></TR><TR><TD>0.48</TD><TD>8.3</TD><TD>2.97</TD></TR><TR><TD>0.50</TD><TD>8.0</TD><TD>2.86</TD></TR><TR><TD>0.52</TD><TD>7.7</TD><TD>2.74</TD></TR><TR><TD>0.54</TD><TD>7.4</TD><TD>2.63</TD></TR><TR><TD>0.56</TD><TD>7.0</TD><TD>2.51</TD></TR><TR><TD>0.58</TD><TD>6.7</TD><TD>2.40</TD></TR><TR><TD>0.60</TD><TD>6.4</TD><TD>2.29</TD></TR><TR><TD>0.62</TD><TD>6.1</TD><TD>2.17</TD></TR><TR><TD>0.64</TD><TD>5.8</TD><TD>2.06</TD></TR><TR><TD>0.66</TD><TD>5.4</TD><TD>1.94</TD></TR><TR><TD>0.68</TD><TD>5.1</TD><TD>1.83</TD></TR><TR><TD>0.70</TD><TD>4.8</TD><TD>1.71</TD></TR><TR><TD>0.72</TD><TD>4.5</TD><TD>1.60</TD></TR><TR><TD>0.74</TD><TD>4.2</TD><TD>1.49</TD></TR><TR><TD>0.76</TD><TD>3.8</TD><TD>1.37</TD></TR><TR><TD>0.78</TD><TD>3.5</TD><TD>1.26</TD></TR><TR><TD>0.80</TD><TD>3.2</TD><TD>1.14</TD></TR><TR><TD>0.82</TD><TD>2.9</TD><TD>1.03</TD></TR><TR><TD>0.84</TD><TD>2.6</TD><TD>0.91</TD></TR><TR><TD>0.86</TD><TD>2.2</TD><TD>0.80</TD></TR><TR><TD>0.88</TD><TD>1.9</TD><TD>0.69</TD></TR><TR><TD>0.90</TD><TD>1.6</TD><TD>0.57</TD></TR><TR><TD>0.92</TD><TD>1.3</TD><TD>0.46</TD></TR><TR><TD>0.94</TD><TD>1.0</TD><TD>0.34</TD></TR><TR><TD>0.96</TD><TD>0.6</TD><TD>0.23</TD></TR><TR><TD>0.98</TD><TD>0.3</TD><TD>0.11</TD></TR></TBODY></TABLE>
 

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i don't have my tank setup yet, but from what i've been reading, stability in your levels is more important than keeping them unnaturally high.


J.
 

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A recent study suggests that raising mag levels may have a positive impact on hair algea. I would certainly do more reading before implementing it on my system if I had algae.

And epsum salts will not add to the salinity. However, it does elevate other levels at a much quicker rate than the mag (wish I could remember what they were), so caution HAS to be used. It was recomended to use 1/4 epsum with 3/4 mag flake to raise mag... Or a mag supplement.
 

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Why not simply purchase a Mg supplement from your LFS? The dissolution of magnesium sulfate will lead to an increase in sulfate anions which I would guess could have a tragic effect on your tank when bound with free radical hydrogen ions. I would bet the end result is far from what you are looking for.

Tom, jump in here with your chemistry lesson, will you? *taps foot waiting*

-Ken
 

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see THIS LINK for some issues in skewing conservative elements and water changes.

I assume that you are using a good SW mix (IO or equivalent). In normal strength seawater (34 to 37 ppt or 3.4 to 3.7% total w/v salts), Magnesium (Mg++) should comprise 3.7% of the total amount of dissolved salts. This comes out to be 1326.7mg/kg seawater based on Cl = 18.2 (or salinity of 35.8ppt) and is one of the conservative elements of seawater. This means that in the open ocean (and to a great extent in marine aquaria), that the ratios of these substances relative to each other does not change. This includes bromine, chlorine, sodium, boron, fluorine, sulfur (as sulfate most often), calcium, potassium, and magnesium. Mechanisms exist for biological sinking of nitrogen, phosphorus, calcium, silica, iron, vandium, carbon, copper, cobalt, manganese, zinc and to some extent, strontium and aluminum to the point that they become nutrients (i.e., factors that can or might limit the growth of biomass) in closed systems, however, there are few if any such mechanisms that significantly remove large amounts of magnesium in this same manner. Magnesium is (in relation to its biological and geochemical rate of use) a conservative element, and is not significantly sinked in most aquaria*. If you are doing a 10% change every 2 weeks, you should not need to add any Magnesium, and in fact if you are, it would be most likely to the detrement of your tank. Even if you were to need to supplement, I would be suspect of the use of Mag sulfate, as it replaces both Magnesium and SULFATE IN EQUIMOLAR AMOUNTS. Magnesium use in biological systems is usually in conjuncion with the use of at least an anion as well as the cation, more often with the use of large amounts of Ca++, in which the Mg is returned to the system without consumption, and when it is, it is not in conjunction with sulfate, so sulfate accumulation becomes an issue over time, slowly providing a means of skewing your conservative proportionality of the seeawater of a system treated with espom salts to boost Mg.

As magnesium is one of the conservative elements of seawater, i.e., that the concentration doesent change relative to its proportion to other elements in the mix, making a series of water changes will restore the proportionality of the mix and would be much more effective overall than using a single salt supplement for the Mg levels in the tank. You want a solution that delivers Magnesium in the amounts you desire without skewing the anions in the solution while doing so.

Just read some of the info at the Kent Marine site of which the part we want is:
<!-- BEGIN TEMPLATE: bbcode_quote -->
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<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Description: Tech•M Magnesium supplement is a ionically balanced product which will safely raise the magnesium level in any marine system without upsetting the ionic balance of the system. Tech•M is very concentrated, containing over 70,000 ppm of cationic magnesium, and is nitrate, phosphate and gluconate free! </TD></TR></TBODY></TABLE>
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If the product is 70,000 PPM Magnesium (not all that concentrated), it would be a 7 gm/100ml solution of Magnesium ions, or a solution of 27.41% MgCl2 (anhydrous MgCl2 is 25.53% magnesium). As we would have difficulty handling anhydrous MgCl2 (VERY hygroscopic!!!) we can use the hexahydrate salt, with a molecular weight of 203.30 gms per mole. The ratio of the weights of the anhydrous salt to the hexahydrate is l : 2.135 , so that if we placed 58.52 gms of the hexahydrate salt in an appropriate volumetric flask and added sufficient water to make the total volume 100 ml, we would have a solution that would supply 7 gms of Magnesium ions for each 100 ml dose, a close approximation of the Kent product in terms of its Magnesium content. Of course, we wouldn't have all the other little additives in their solution, but THAT to me is a bonus.
AN Example of how to use such a product:
In nobby's tank, 250 UK gallons is a volume of 1135 liters, or 300 gal US. If our goal is 1300mg/l of Mg, and you measured 1200 mg/l AT 35 PPT SALINITY (very important to have salinity adjusted), then you would have a deficit of 113 GMS of Magnesium, requiring 16.21 liters of the magnesium solution we just made... quite a bit, even in relation to the size of this system.
If this system has been supplemented for a long period with a 2 part additive, then the magnesium is being crowded out by the increasing amounts of sodium (from the sodium bicarbonate in the alk supplement) and the chloride (from the CaCl2 in the calcium part) present in equimolar amounts of the ca(equimolar x 2) and alk supplied. Craig Bingman suggests such systems have a 50% water change every 12 months to correct for the increasing amounts of sodium and chloride left behind when corals uptake the calcium and bicarbonate/carbonate from the water column. With this taking place, increasing sodium and chloride reduce the amount of Magnesium in the water column be increasing their relative proportions in the salinity specific gravity mix. This requires more water to maintain the salinity at 1.026 (because there are now more ions/solutes in the water column). The Magnesium is removed as we remove "salt" from our system as the salinity increases with a fixed desired volume. Salinity increases over time again, and we remove more "salt" by taking out a gallon of the seawater again, and so on... eventually with some of the computer modeling that Craig has done, the water column can become primarily Sodium and Chloride above all other ions. With such a relatively large volume, it may behoove you to have your conservative proportions evaluated, then decide whether it is better to do one big water change, or try to reestablish those proportions with additives.
This should give you an idea of where we ar going with the proceses. something with a balance of ions and anions as we would see with seawater and Mg would be much more approprite, especially if the losses of Mg are related to 2 part additives and/or salt creep losses from the tank (the most common losses of Mg). Just a few random thoughts on the subject of Mg supplementation in closed systems.
For those of you who are making your own Mg supplements due to the cost of the professional products, there is a much less expensive alternative that you can make that results in less ionic disruption than using either pure magnesium chloride or pure magnesium sulfate. Natural seawater (35 parts per thousand salinity) has 550 millimoles per liter chloride ion and 28 millimoles per liter sulfate ions. Magnesium is accompanied by two moles of chloride per magnesium in magnesium chloride, and one mole of sulfate per magnesium in magnesium sulfate. Calculating the ratio of the anions of these two salts (how convenient, Sulfate and Chloride are the two major anions in seawater...), we can demonstrate that mixing 10 moles of magnesium chloride with one mole of magnesium sulfate will result in a mixture that had almost exactly the chloride/sulfate ratio of natural seawater!!!

As most of you won't have good balances at home, measuring these two substances can be accomplished for aquaria use by using 10 volumes of the chloride to 1 volume of the sulfate (espon salts), as the densities of these two salts is about the same (1.67 grams per cubic centimeter for Epsom salts and 1.56 grams per cubic centimeter for magnesium chloride hexahydrate). Use of this supplement will not appreciably disrupt the ionic ratios of the major two anions in seawater, which is my major bone of contention with the use of Magnesium supplements in general.

Addressing the issue on shifting salinities with B-ionic and similar 2 part additives is the subject of part 1 and the corresponding Part 2 of Craig Bingman's article in the Aquarium Frontiers archive.
I could prolly spend a great deal of time on this subject, but suffice it to say that most of the Magnesium shifts we see are due to incorrect salinities or mixing our ASW with one of the mixes that cuts costs by cutting the Mg content (It is NOT IO). In closed systems, there can be some precipitation of Magnesium as the Hydroxide, but very little (with limewater, this only occurs in the direct vicinity of the area of addition to the water column, if at all.) Some hermatypic organisms (primarily coralline algae) and sclerite-forming soft corals do make a "dirty" calcite or aragonite, especially the corallines, of which some spp. may incorporate up to 30% of their calcium deposits as Magnesium Aragonite (heh, if you will
). Fortunately, these sinks account for very little of the total Magnesium in the water column (think in terms of how much accreation actually occurs with coralline...). Very old systems with large deposits of coralline may see this, but regular water changes over time will have supplied all the magnesium that is needed to supplement the growth and development of the coralline.

HTH


related issues: http://www.thereeftank.com/forums/showthread.php?s=&threadid=22075


* There are a few species of calcareous algae that do sink up to 4% of their biomass as mangneseium carbonates, but these are few and far between, and do not account for a significant balance of crustose algae in aquarium systems.
 
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