Origami July 30, 2009 Share July 30, 2009 Ok so i did a little test on my Aqua Medic kalkstirrer with Brightwell Kalk +2 in it. I collected around 3mL of effluent, waited 15 mins for the sediment to settle, then decanted 1mL of the effluent water(not crusty top layer in the sample and no precipitate from the bottom in the sample) added it to my magnesium test ( seachem reef status) and also added the 1mL of zero (0) TDS ro/di water because the test calls for a sample of 2mL. Anyway I ran the test and I got about 1000mg/L of magnesium. I should add that one of the steps in this brand of test kit actually precipitates most if not all of the calcium as to reduce or eliminate calcium interference in the test. So answer me this, how would i get 2000mg/L of magnesium in my effluent if the MAG precipitate in the kalkstirrer and never leaves the chamber b/c you say it is not soluble. Also, just to be sure seachem provides a reference sample to check the accuracy of the reagents and the test is spot on. Sean Good question, Sean. I use the same test. That's why I proposed running it (above). I'll run your results by Boomer over at RC and see what he has to say. Link to comment Share on other sites More sharing options...
Origami July 30, 2009 Share July 30, 2009 (edited) Sean, here's Boomer's response to your question. As you can see, it gets into some pretty complicated stuff (way beyond me). I haven't any opinion on what it means from the practical standpoint of using a stirrer. I have followed up with additional questions for him, however. I've provided those as well. Let's see what he has to say. (Boomer is one of RC's chemist-types. RHF has been on sabatical for the last six weeks and is not expected back until early Fall, otherwise I'm sure he'd weigh in. RHF, Boomer & Bertoni are RC's chemistry forum heavyweights. Our own Cliff Babcock - Highland Reefer - is a frequent contributor, too.) Here's Boomer: So answer me this, how would i get 2000mg/L of magnesium in my effluent if the MAG precipitate in the kalkstirrer and never leaves the chamber b/c you say it is not soluble. and waited 15 mins for the sediment to settle Stokes Law of Setting Velocity V0 = 0.0555 x ( ơ - p )gD2 / ŋ V0 = Settling Velocity ơ = Density of the particle p = Density of the fluid g = Gravity D = Particle diameter ŋ = Viscosity In 15 min you will only get particles of > 0.05 mm/ 50 microns. It takes 4 hrs to get to silt size particles. And it takes > 40 hrs of settling to get all the particles to include clay sized. And all this is using a 1000 ml graduated tube. 15 min does not mean squat and 50 microns is huge. Free swimming Ick parasites are @ 50 microns. When we try to filter out particles out of an effluent 10 microns is min. Purple Up uses powdered aragonite, which is 10 microns. And he is only collecting particles 5 times that size. Human hair starts at 70 microns or bigger. You can see 40 micro particles. So, # 1 most of that Mg(OH)2 is going right into the effluent. #2 the kit and its reagents are reacting with that Mg(OH)2 and giving false Mg++ readings. And playing with a 2 ml sample will not cut it at all. He needs a 100 mm tube min. filled for this and take a reading at the 20 mm mark in 24 hrs. min. ******* So, that was Boomer's initial thoughts. I followed up with the following and await a response: "Brilliant, Boomer. Thank you. "I have, what I hope to be, a couple of straightforward follow up questions that you may be able to weigh in on. "First, it seems that he took his initial (small) sample from the effluent toward the top of his kalk stirrer. So the settling time he's talking about is not the settling time in that vessel, but of the small sample itself. It is an operational kalk stirrer, so I assume that it was in a form of "equilibrium" from an operational point of view (including possibly the suspension of small particles of Mg(OH)2 which might be held so by the mechanism of constant stirring). "The second question is also a practical one, and is foreshadowed by the last. Could the constant stirring of the reactor vessel maintain Mg(OH)2 particles in constant suspension so it was available in the effluent? If that were plausible, the net effect would be to dose Mg(OH)2 into the aquarium's lower pH environment where it would dissociate and deliver magnesium to the tank would it not?" (So, Bob, you don't need to be a chemist in this hobby, but it can be useful at times!) Edited July 30, 2009 by Origami2547 Link to comment Share on other sites More sharing options...
mchippo July 30, 2009 Share July 30, 2009 Hey!! They didn't tell me I was gonna hafta take chemistry for this hobby!! Plumbing, yes... Carpentry, yes... Animal Husbandry, yes... Electronics, yes... Optical theory, yes... And now I hafta do chemistry, too?!?!?! bob You forgot Banking and Finance as well as Marriage Counselling Link to comment Share on other sites More sharing options...
F&Fmgr July 30, 2009 Share July 30, 2009 Sean, here's Boomer's response to your question. As you can see, it gets into some pretty complicated stuff (way beyond me). I haven't any opinion on what it means from the practical standpoint of using a stirrer. I have followed up with additional questions for him, however. I've provided those as well. Let's see what he has to say. (Boomer is one of RC's chemist-types. RHF has been on sabatical for the last six weeks and is not expected back until early Fall, otherwise I'm sure he'd weigh in. RHF, Boomer & Bertoni are RC's chemistry forum heavyweights. Our own Cliff Babcock - Highland Reefer - is a frequent contributor, too.) Here's Boomer: So answer me this, how would i get 2000mg/L of magnesium in my effluent if the MAG precipitate in the kalkstirrer and never leaves the chamber b/c you say it is not soluble. and waited 15 mins for the sediment to settle Stokes Law of Setting Velocity V0 = 0.0555 x ( ơ - p )gD2 / ŋ V0 = Settling Velocity ơ = Density of the particle p = Density of the fluid g = Gravity D = Particle diameter ŋ = Viscosity In 15 min you will only get particles of > 0.05 mm/ 50 microns. It takes 4 hrs to get to silt size particles. And it takes > 40 hrs of settling to get all the particles to include clay sized. And all this is using a 1000 ml graduated tube. 15 min does not mean squat and 50 microns is huge. Free swimming Ick parasites are @ 50 microns. When we try to filter out particles out of an effluent 10 microns is min. Purple Up uses powdered aragonite, which is 10 microns. And he is only collecting particles 5 times that size. Human hair starts at 70 microns or bigger. You can see 40 micro particles. So, # 1 most of that Mg(OH)2 is going right into the effluent. #2 the kit and its reagents are reacting with that Mg(OH)2 and giving false Mg++ readings. And playing with a 2 ml sample will not cut it at all. He needs a 100 mm tube min. filled for this and take a reading at the 20 mm mark in 24 hrs. min. ******* So, that was Boomer's initial thoughts. I followed up with the following and await a response: "Brilliant, Boomer. Thank you. "I have, what I hope to be, a couple of straightforward follow up questions that you may be able to weigh in on. "First, it seems that he took his initial (small) sample from the effluent toward the top of his kalk stirrer. So the settling time he's talking about is not the settling time in that vessel, but of the small sample itself. It is an operational kalk stirrer, so I assume that it was in a form of "equilibrium" from an operational point of view (including possibly the suspension of small particles of Mg(OH)2 which might be held so by the mechanism of constant stirring). "The second question is also a practical one, and is foreshadowed by the last. Could the constant stirring of the reactor vessel maintain Mg(OH)2 particles in constant suspension so it was available in the effluent? If that were plausible, the net effect would be to dose Mg(OH)2 into the aquarium's lower pH environment where it would dissociate and deliver magnesium to the tank would it not?" (So, Bob, you don't need to be a chemist in this hobby, but it can be useful at times!) Thats great, however Tom, and by using the same test kit you would know this, but the cotton filter step removes most particles . And if he is saying that I should be able to see the mag sediment than after that cotton filter step i could not see anything but clear water. So my assumption would be that yes some particulate magnesium precipitate does come through the effluent but two things: #1 like you said does its dissociate into the water column? right? And #2 since ive filtered all of the mag sediment through a step in the test my reading should only be of Ionic MAG, correct? Thanks for looking into it Tom Sean Link to comment Share on other sites More sharing options...
Origami July 30, 2009 Share July 30, 2009 (edited) Thats great, however Tom, and by using the same test kit you would know this, but the cotton filter step removes most particles . And if he is saying that I should be able to see the mag sediment than after that cotton filter step i could not see anything but clear water. So my assumption would be that yes some particulate magnesium precipitate does come through the effluent but two things: #1 like you said does its dissociate into the water column? right?And #2 since ive filtered all of the mag sediment through a step in the test my reading should only be of Ionic MAG, correct? Thanks for looking into it Tom Sean Sean, the cotton filter used in the seachem kit does not filter particles of this size. They're way too small. He's also saying that 40 micron particles are barely resolvable to the human eye (maybe not mine!) and that these smaller particles would not even be visible. Also, nearly all of the the magnesium, according to the chemistry, should be in Mg(OH)2 form at the high pH of kalkwasser. It won't be in ionic form until the pH drops below 10. The test kit probably does this early on with the first drop of reagent that's used to precipitate out the calcium and the strontium prior to the filtration step. Let's see what he has to say. I'm interested in running a few tests myself so I may stop by this weekend to collect some of your effluent and water if you'll let me. It seems to me that we should be able to answer this question from a practical perspective. I think you'd agree with me there. Results may vary, though, from installation to installation. One of the first guys to post in response to my question said that he'd used Kalk+2 for a while but had to continue dosing magnesium at his old rate. So, from his perspective, he had Kalk +1 or even Kalk + 0. By the way, do you ever test for strontium? Edited July 30, 2009 by Origami2547 Link to comment Share on other sites More sharing options...
jnguyen4007 July 30, 2009 Author Share July 30, 2009 So does all this mean that it is best to add magnesium separately from the kalk stirrer? Link to comment Share on other sites More sharing options...
flowerseller July 30, 2009 Share July 30, 2009 So does all this mean that it is best to add magnesium separately from the kalk stirrer? I have to or I can't keep it up. hmm, somehow that does not sound right. the Mg that is. Link to comment Share on other sites More sharing options...
Origami July 30, 2009 Share July 30, 2009 So does all this mean that it is best to add magnesium separately from the kalk stirrer? Best? I don't know. It's probably the most widely used option, though. My curiosity, right now, is centered on the question of whether or not the Brightwell Kalk+2 formulation delivers a reasonable amount of magnesium to the tank. Sean, can you measure the pH and alkalinity of your (filtered) kalk stirrer effluent? I'm interested in knowing if the formation of (particulate) Mg(OH)2 is influencing these parameters. Link to comment Share on other sites More sharing options...
dschflier July 30, 2009 Share July 30, 2009 And this is why I love WAMAS. Great thread Link to comment Share on other sites More sharing options...
Origami July 30, 2009 Share July 30, 2009 (edited) More stuff for lovers of this stuff.... From sowellj: Without knowing the initial concentrations of Mg/CaOH2 its a bit tough to say. If you look at the solubity constants for Mg/CaOH2, calcium hydroxide is roughly 100,000 times more soluble, if they are at equal concentrations. These two things in solution will also be influenced by the common ion effect. Once you reach the saturation point and begin forming percipitates, ions still remain in solution, it is just the ions that exceed the solubility constraints that form the precipitate. Not taking the common ion effect into account (it will further reduce solubility in this case), I get soluble concentrations of ~ 160 uM, for magnesium hydroxide, well below the calculated concentration the tester came up with. So ... its likely that there was suspended particles ... or perhaps a specificity issue with the test ... From me: [i[suspended particles is an option I'm considering (hence the question to Boomer). This is another possibility that I'm considering: The seachem test, as I recall, goes through a step which is supposed to co-precipitate and filter calcium and strontium to eliminate confounding. If this step was insufficient (because the calcium concentration of kalkwasser is substantially higher than ASW and the test is designed to test ASW, hence the amount of reagent was probably sized to precipitate much less than was available in the sample) to drive all the calcium out of the test sample, then it's likely there's still substantial calcium present in the filtered effluent. If that's the case, it could be that this residual calcium is confounding the test results.[/i] Edited July 30, 2009 by Origami2547 Link to comment Share on other sites More sharing options...
reefmontalvo July 30, 2009 Share July 30, 2009 More stuff for lovers of this stuff.... From sowellj: Without knowing the initial concentrations of Mg/CaOH2 its a bit tough to say. If you look at the solubity constants for Mg/CaOH2, calcium hydroxide is roughly 100,000 times more soluble, if they are at equal concentrations. These two things in solution will also be influenced by the common ion effect. Once you reach the saturation point and begin forming percipitates, ions still remain in solution, it is just the ions that exceed the solubility constraints that form the precipitate. Not taking the common ion effect into account (it will further reduce solubility in this case), I get soluble concentrations of ~ 160 uM, for magnesium hydroxide, well below the calculated concentration the tester came up with. So ... its likely that there was suspended particles ... or perhaps a specificity issue with the test ... From me: [i[suspended particles is an option I'm considering (hence the question to Boomer). This is another possibility that I'm considering: The seachem test, as I recall, goes through a step which is supposed to co-precipitate and filter calcium and strontium to eliminate confounding. If this step was insufficient (because the calcium concentration of kalkwasser is substantially higher than ASW and the test is designed to test ASW, hence the amount of reagent was probably sized to precipitate much less than was available in the sample) to drive all the calcium out of the test sample, then it's likely there's still substantial calcium present in the filtered effluent. If that's the case, it could be that this residual calcium is confounding the test results.[/i] Tom, After the propsed question was asked I will plan on tonight to test the Mg levels in the tank. I have not dosed Mg in sometime since using this product so my numbers will be soley based on the Kalk+2. Link to comment Share on other sites More sharing options...
Origami July 30, 2009 Share July 30, 2009 Tom, After the propsed question was asked I will plan on tonight to test the Mg levels in the tank. I have not dosed Mg in sometime since using this product so my numbers will be soley based on the Kalk+2. Without having a control, Chris, it only gives us half of a picture. Boomer appears to be getting a little snippy in the discussion over at RC.... http://www.reefcentral.com/forums/showthre...hreadid=1679712 As you can see, I'm trying to remain diplomatic. I really don't know the reason behind Sean's high measurement. I suspect confounding of the test - that is, that the test confused calcium with magnesium when all the calcium was not removed in the first step of the test. That's a suspicion, though. It's not confirmed. I think the test protocol that I've suggested will give us better data. Still, if magnesium is finding it's way through the kalk reactor by way of particles in suspension (they have to be particles, you see, because the magnesium could not exist in any other form (except as a metal perhaps) in the highly alkaline environment of kalkwasser) it's not likely to be a very controlled form of dosing but will be dependent upon the density of particles which, in turn, depends on the mechanics of the stirrer and the size of the particles that are allowed to form. This means of dosing is not very controlled when compared to plain vanilla kalkwasser solution because the concentration of saturated kalkwasser is well known and very consistent (as long as it's saturated). Link to comment Share on other sites More sharing options...
reefmontalvo July 31, 2009 Share July 31, 2009 Without having a control, Chris, it only gives us half of a picture. Boomer appears to be getting a little snippy in the discussion over at RC.... http://www.reefcentral.com/forums/showthre...hreadid=1679712 As you can see, I'm trying to remain diplomatic. I really don't know the reason behind Sean's high measurement. I suspect confounding of the test - that is, that the test confused calcium with magnesium when all the calcium was not removed in the first step of the test. That's a suspicion, though. It's not confirmed. I think the test protocol that I've suggested will give us better data. Still, if magnesium is finding it's way through the kalk reactor by way of particles in suspension (they have to be particles, you see, because the magnesium could not exist in any other form (except as a metal perhaps) in the highly alkaline environment of kalkwasser) it's not likely to be a very controlled form of dosing but will be dependent upon the density of particles which, in turn, depends on the mechanics of the stirrer and the size of the particles that are allowed to form. This means of dosing is not very controlled when compared to plain vanilla kalkwasser solution because the concentration of saturated kalkwasser is well known and very consistent (as long as it's saturated). Tom, I just finished my test and I found between 1290 to 1260 ppm of Mg in my tank test with a Salifert kit. I think the Kalk+2 is a major contributor to the Mg levels. I hope this helps with those snippy folks. And Tom you have been to my house and seen my setup so you know this is a real assesment. Link to comment Share on other sites More sharing options...
Origami July 31, 2009 Share July 31, 2009 Sounds good, Chris. What salt do you use again and what's your water change regimen? Link to comment Share on other sites More sharing options...
reefmontalvo July 31, 2009 Share July 31, 2009 Sounds good, Chris. What salt do you use again and what's your water change regimen? I currently try to at least do 5 gallons a week with Reef Crystals, but I have not done a water change in about 3 weeks. So I feel the Mg number is a good indicator of what the Kalk is actually doing. Link to comment Share on other sites More sharing options...
Origami July 31, 2009 Share July 31, 2009 Here's an interesting post that goes, not only to precipitation, but also that takes a hard look at how much magnesium is in the product according to the label: http://www.reefcentral.com/forums/showthre...hreadid=1503312 And this is a very interesting article, too. RHF uses spectroscopy to compare how much magnesium is available in his kalkwasser with how much was in the kalk powder to start with. http://www.advancedaquarist.com/issues/dec2003/chem.htm (Must be nice to have access to such tools when faced with questions such as these!) Link to comment Share on other sites More sharing options...
Origami July 31, 2009 Share July 31, 2009 I currently try to at least do 5 gallons a week with Reef Crystals, but I have not done a water change in about 3 weeks. So I feel the Mg number is a good indicator of what the Kalk is actually doing. Chris, RC should mix up higher than ~1300 ppm Mg. The latest numbers I've read are that, at 1.0264 sg, it should mix up to around 1440 ppm Mg. If this is true, you may be consuming more than you're replenishing. Link to comment Share on other sites More sharing options...
dschflier July 31, 2009 Share July 31, 2009 Just to bring the discussion back to the original question. From the research I did, when I first began looking into buying bulk calcium hydroxide, I discovered it was likely that most US aquarium companies get their Calcium hydroxide from one company. Their used to be three main companies selling Calcium hydroxide, Mississippi Lime company, Ash grove and USG. USG went out of business or at least doesn't sell Calcium hydroxide anymore and Ash grove was acquired by Mississippi Lime. So the base product of most companies likely comes from Mississippi lime co. They sell various grades of Lime. From my understanding 'commercial' is not a grade used in the industry, it may be used for advertisement. They do not sell Regent or Pharma grade, but they sell their Calcium hydroxide to a company called Mallincroet which does further testing and will provide Regeant grade at 500g for $58 so I doubt anyone is using this. Their are other companies that sell Reagent grade and Pharma grade Calcium as well. Besides not being cost effective I also found that just because it is reagent grade doesn't mean it is more pure. In many cases it is the same product that has gone through much more testing. What I was told by someone at Malinckrodt is that Pharma, food and reagent grade have different criteria in order to be classified in one of those categories but often are the same product. She said "You are paying for a lot of analysis." It appears some companies may add other things to the product which may differentiate their product from others. Link to comment Share on other sites More sharing options...
DJBoy98 July 31, 2009 Share July 31, 2009 so what you are saying is that Pickling Lime is pretty much the same as the commercial grade minus the additives? Link to comment Share on other sites More sharing options...
dschflier July 31, 2009 Share July 31, 2009 All I am saying is that, it is likely that the Calcium hydroxide comes from the same place. I do not have any way of knowing how it is stored or kept after it is shipped to other businesses. To answer your question I would say it is likely. Link to comment Share on other sites More sharing options...
Origami July 31, 2009 Share July 31, 2009 Don't forget, though, that Mississippi Lime has various grades of product that they sell as well. They may be a single source, but they have different purities of their product available for different uses. Their standard product, for example, is apparently used in industrial applications for such uses as flue gas treatment and water treatment plants: http://www.mississippilime.com/products/hydratedlime Link to comment Share on other sites More sharing options...
dschflier July 31, 2009 Share July 31, 2009 Don't forget, though, that Mississippi Lime has various grades of product that they sell as well. They may be a single source, but they have different purities of their product available for different uses. Their standard product, for example, is apparently used in industrial applications for such uses as flue gas treatment and water treatment plants: True. I think that is the most important part. For aquarium use companies are not required to buy food grade which is more expensive then the calcium hydroxide used in industrial applications. Link to comment Share on other sites More sharing options...
flowerseller July 31, 2009 Share July 31, 2009 The stuff we got in a GB Dave ran about 6 years ago was the vitacal. That's the same stuff from the last GB Dan ran 2-3 years ago. I've used it since but there's always room for discussion. I can say the Calcium Hydroxide I used to use from Sigma Chemical was better, just too darn expensive. It came with a "lot#" and a faxback info sheet. It was always 98.5 or higher pure. I just looked at the last sheet and the Mg was1.3% Link to comment Share on other sites More sharing options...
reefmontalvo July 31, 2009 Share July 31, 2009 Just to bring the discussion back to the original question. From the research I did, when I first began looking into buying bulk calcium hydroxide, I discovered it was likely that most US aquarium companies get their Calcium hydroxide from one company. Their used to be three main companies selling Calcium hydroxide, Mississippi Lime company, Ash grove and USG. USG went out of business or at least doesn't sell Calcium hydroxide anymore and Ash grove was acquired by Mississippi Lime. So the base product of most companies likely comes from Mississippi lime co. They sell various grades of Lime. From my understanding 'commercial' is not a grade used in the industry, it may be used for advertisement. They do not sell Regent or Pharma grade, but they sell their Calcium hydroxide to a company called Mallincroet which does further testing and will provide Regeant grade at 500g for $58 so I doubt anyone is using this. Their are other companies that sell Reagent grade and Pharma grade Calcium as well. Besides not being cost effective I also found that just because it is reagent grade doesn't mean it is more pure. In many cases it is the same product that has gone through much more testing. What I was told by someone at Malinckrodt is that Pharma, food and reagent grade have different criteria in order to be classified in one of those categories but often are the same product. She said "You are paying for a lot of analysis." It appears some companies may add other things to the product which may differentiate their product from others. I feel Mg is a very important aspect of Kalkwasser, even if it is not in the mixture. Tom, I think your right about my Mg consumption. But I also know I'm going thru Ca probably in the same speed. Since there both consumed by the flesh of the corals now for Strontium I think it is used in the calcium absorption process. But I'm not really sure all I know is there are trace amounts of Strontium in the tank. Link to comment Share on other sites More sharing options...
DJBoy98 July 31, 2009 Share July 31, 2009 You can get Mg also in quality salts such as D2D Ocean. It keeps my Mg at 1300s. With a Ca reactor you can get strontium along with Ca. Link to comment Share on other sites More sharing options...
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