Domolite lime and other lost arts... - Page 3

StirCrazy · #21 01-23-2002, 10:44 PM

<blockquote>quote:<hr>Originally posted by powerreef:
I have been keeping a SW aquariums for 19 years and am one of those that used to used Dolomite as a substraight.<hr></blockquote>

How long was your tank running on Dolomite?

<blockquote>quote:<hr>Originally posted by powerreef:
Thier have been many studies measuring the effect Magnesuim on aquaria, and it has been found that animals exposed to high mag concentrations in SW begin to show significant relaxation (ie: works as anaethesia) and prolonged expose causes mortallity in almost all species..<hr></blockquote>

Can you post some of the links to thease studies please, I haven't been able to find anything on this yet and I would liek to read it.

<blockquote>quote:<hr>Originally posted by powerreef:
Another thing that scares me is the effect that Magnesium has on alk and cal. As i'm sure you know magnesium will slow the percipitation of cal.by attaching its ion to the carbonate ion of calcium carbonate. What effect would this have on calcium if it sat in a tank with such high levels of mag<hr></blockquote>

you would be able to obtain higher calcium levels.

<blockquote>quote:<hr>Originally posted by powerreef:
Another thing to remember is in seawater, more than half of the carbonate ions present at any given point in time are ion-paired to magnesium, and this substantially reduces the free concentration of carbonate ions available to precipitate with calcium.<hr></blockquote>

this is TRUE, and it is a good thing. if the Mg didn't pair with the carbonate ions the calcium would.. and if calcium did pair it would drop out of solution and create more sand. exactly what you don't want . now because the magnesium is causing more calcium to stay in solution that means there is more calcium available for your coarls and other creatures (that require calcium) this is one of the benifits of adding magnesium to your system, it allows you to have HIGHER Ca levels. I would hazard to guess that anyone with over 450ppm ca has a higher magnesium level than natural sea water.

<blockquote>quote:<hr>Originally posted by powerreef:
I geuss what i'm trying to say is that magnesuim at natural levels is good , but at high levels the fact that joins with other minerals and chemicals and produces biproducts is not good.<hr></blockquote>

ok you confused me on this one and I wasn't sure what to say but Magnesium is fairly non reactive and dosent combine with other metals. to back this up I will use a quote from a chemmist who is a reefer.

"Interestingly, the average residence time for a magnesium ion in seawater is tens of millions of years, substantially longer than calcium (a few million years) and aluminum (100 years), but less than sodium (about 250 million years). In a sense, this is an indication of how reactive magnesium is: it stays in seawater a long time because it's fairly unreactive, but it does get taken out of solution more readily than does sodium." by Randy Holmes-Farley

now what I think you might have been talking about is what he referd to as "Poisoning of Growing CaCO3 Surfaces". in fact the magnesium doesen't combine with the calcium but the magnesium carbonate forms a coating around the calcium carbonate and when it is large enuf it precipatates out of solution. remember if something falls out of solution it is no longer a concern as it can't interact. this is one of the ways the level of magnesium in a solution is controled.

I have to say this post made me do a lot more searching and I had to reread a lot of stuff to be sure on what my instints were. now having said all that I am interested in reading thease studies on the higher magnesium levels you were talking about.

Steve

powerreef · #22 01-23-2002, 11:52 PM

Hey steve I not tring to say that the use af a Dolomite bed will cause all life as you know it in your tank to die, I'm just saying is that thier are a lot of untested results of such a substraight, and if we concider the larger ammount of money we pay for corals, gadjets and so on why cheap out here. I'll try to answer some of your questions.
<blockquote>quote:<hr>How long was your tank running on Dolomite?
<hr></blockquote>
my tank was up and running for about 3 years using this stlye and o combination using dolomite. This said we did not any real corals to talk of back then it was basically white sand coral skelitons and the nastest sea cr\itter we could get.

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Can you post some of the links to thease studies please, I haven't been able to find anything on this yet and I would liek to read it.

I will have to search them out , but i will get them to you tommorrow.heres one
http://www.animalnetwork.com/fish/li...&RecordNo=2856

ihad discussed the effect mag has on cal in the tank, and you made a general statement that it was good, and indeed it is but at normal levels, what would it be if the mag was increased to to 10 times its natural level.magnesium has a big impact on the rate of precipitation of calcium carbonate. so would that concintration all most reduce calcium precipition to nil or just slightly, would this give us calcium super saturated SW, would this be ok? I dont know do u.

I stated mag ions attach through pairing with other minerals. oopps i meant other ions from other elements.

thier were a couple of things i had stated that you had not retorted on, as in the adverse effects on aquaria inhabitants, that should be something for you to concider. Here is a section out of an article by Craig Bingman, a pretty well known author on aquaria . it reads as follows

Dangers of excessively high or low magnesium

Some aquarists are apparently adding magnesium supplements to their aquariums without performing any testing for magnesium levels. This is a potentially dangerous practice. I can point to no evidence that higher than natural seawater magnesium concentration has a beneficial effect on marine organisms. However, there is evidence that higher than natural seawater concentrations of magnesium can harm marine organisms.
Magnesium salts have been used as a “chemical shucking aid” on oysters and other shellfish for many years (Whyte and Carswell 1983). Magnesium chloride is also used as a relaxant or anaesthetic in pearl oyster culture (Norton et al. 1996). Namba et al. (1995) report persistent relaxation of the adductor muscles of the oyster, Crassostrea gigas, when exposed to solutions of magnesium chloride. The degree of relaxation was dose and time dependent. Higher concentrations of magnesium chloride and longer periods of exposure increased the number of individuals showing persistent relaxation. Significant relaxation was observed in groups of animals exposed to concentrations of magnesium only six times higher than seawater for periods as brief as 30 minutes.

Culloty and Mulcahy (1990) indicate that magnesium salts make an inexpensive anaesthetic agent for Ostrea edulis. In studies of anaesthetic agents for the scallop, Pecten fumatus, Heasman et al. (1995) found that magnesium chloride at 0.31 molar was a good anaesthetic. However, magnesium sulfate at the same dose caused excessive post-anaethesia mortality, a finding that may be interesting and relevant to individuals who use magnesium sulfate heptahydrate (Epsom salts) as a magnesium additive.

anyway it just doesnt seem worth it buddy

DJ88 · #23 01-24-2002, 01:16 AM

We meet again Victor.. [img]images/smiles/icon_biggrin.gif[/img]

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there is a little secret that I use when buying lime

Isn't that something you should share with others to minimize the chances of getting a bad that may be contaminated? Hmm???? Where was this tidbit when you were suggesting dolomite? Keeping the safer bags for yourself were you?

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if you do a search on RC...there is tons of info on this topic

I did before you posted this. Here is a rough breakdown of what I found.
[list][*]9 were for adding a tiny amount of dolomite to a Ca reactor to increase Mg levels.[*]6 Using as a substrate yourself, Yellow tang & hatton3(asking about cycling with dolomite 3 posts)[*]3 of Steve asking about dolomite[*]4 Used with UGF in the past[*]2 Used as kalk substitute[*]2 Beginner mistakes[*]2Grain size (linked to reefs org)[*]Looking for Southdown. Recommended dolomite by person above to reefs.org.[*]Taking dolomite out[*]Dr Ron recommending to get rid of UGF and Dolomite as substrate.[*]Troy talking to Randy Holmes-Farley where he recommends keeping an eye on Mg levels[*]Using Dolomite with UGF and wanting to switch.[*]Scooter asking if it was good to Dr Ron[*]Store selling old bags of.[*]Worst purchases.[*]Talking about progression of substrates trough the progression of the hobby. listed as a substrate used with UGF's[*]Silica sand use. Was in the thread.[*]Flame Angel bought the wrong dolomite[*]Keeping Mg levels up.[*]Looking for cheap substrate[*]Dolomite sandbed doesn’t buffer as well as aragonite or oyster shells. Lower pH. Tests done over two months in Salt Water.[*]Super calc gold looking like[*]Spelling mistake.

That is a summary of Dolomite on RC. Three people using it. Of which I think you are the only one using it in a DSB. So the only one who will see what will happen to the MgCO3 in a DSB. I did see lots of uses in a Ca reactor to INCREASE Mg levels in the system. Once again I wonder what will happen as the Ph in your DBS drops and the Mg starts to enter into your water column. You according to your tank description only do in-frequent water changes. And that worries me. Randy Holmes-Farley said that you should keep and eye on your Mg levels and I hope you do. I know some will precipitate out but I bet you can get your concentration of Mg up beyond levels safe in your system. It is a hunch I am gathering from the responses and articles I am seeing on the boards.

To me other than you and two others using dolomite(one was a 12 gallon FO), it isn't in use very much. I searched on reefs.org and found two posts. Both by the same author. In the past when there wasn't the abundance of substrates(Aragonite based) as there is now it was used solely with an UGF. Not in a DSB so those can be an example of it's use but not when used in a DSB. That is a while different creature.

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Why should the newbee believe me in 100% confidence

To a newbie in this hobby you are very knowledgeable. You have a tank up and running. They don't know for how long or how short. All they see is you making a recommendation for Dolomite as a substrate. And that you are using it. It took quite a few posts to get your secret out of you about getting bags in the middle of the stack.. lol. [img]images/smiles/icon_wink.gif[/img] When someone sees the possibility of saving a few dollars in this hobby their eyes get cloudy as to all the things involved. I have done it. I'll admit it. As someone new all they will have to see is someone who has many posts recommending something and they will do it. Hey these people will go and buy a skimmer that is good for a 40 gallon tank and throw it on something over 100 gallons if they see someone saying they do it on a board. Heck I bought a SeaClone for a 90 gallon tank!!!! I thought it was enough. [img]images/smiles/icon_eek.gif[/img] [img]images/smiles/icon_rolleyes.gif[/img]

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Today, salt mixes have higher than normal magnesium levels to compensate

According to this study(link below) done not all are so. Most are lower. I use Instant Ocean and it is almost identical. Mg levels in synthetic sea salt and Natural Sea Water.

So what happens if the Mg levels are increased even higher? That is my point. I use Iocean and it keeps my levels at or near NSW. To me your levels will increase over time. A noted chemist in this hobby has said as such. What do you say in regards to that?

<blockquote>quote:<hr>So, if the dissolution rate of increase is slow enough, the preciptation and dissolution should find an equilibrium where both are happy.
<hr></blockquote>

You are sure about this? Once again, Randy Holmes Farley has said that you should keep an eye on these levels. If there was no reason to worry about it increasing why would he mention it? But that is me interpreting a chemist and what he is saying.

I guess in time we will see. Hopefully it isn’t for the worse.

StirCrazy · #24 01-24-2002, 01:21 AM

powerreef, all is good, I am debating this as I want to find out more. how long ago was this you were using it? and didn't you have mushrooms or softies or such?

that article is the one I quoted from by Randy Holmes-Farley, I have probably read that about 20 times now hehe

I totaly agree about the epsom salts. aka magnesium chloride. if you check you will find that this is used as magnesium seams to have a great bonding ability with chlorine and as a chloride you have a wonderfull anaesthetic but as free magnesium or as magnesium carbonate you would not get the same results. remember that the second part of the equasion
sence 0.0453 moles per kilogram = 1100 parts per million, you would have to have a Mg level of
7525ppm in a "salt" form just to be a good anaesthetic.

Steve

StirCrazy · #25 01-24-2002, 01:38 AM

hey here is a link for Darren [img]images/smiles/icon_smile.gif[/img]
http://www.aquariastore.com/aquaria/...203?1,34607706

and this is from Aqualink on setting up a plenium

"Bob Goemans wrote that this area will have a pH of 7.6 or so, and that dolomite is the preferred substance. Dolomite is less calcerous than crushed coral, and therefore will not dissolve as much at this lowered pH."

Steve

StirCrazy · #26 01-24-2002, 01:54 AM

<blockquote>quote:<hr>Originally posted by DJ88:
You are sure about this? Once again, Randy Holmes Farley has said that you should keep an eye on these levels. If there was no reason to worry about it increasing why would he mention it? But that is me interpreting a chemist and what he is saying.

<hr></blockquote>

ok Darren just a couple things [img]images/smiles/icon_smile.gif[/img] if you are going to use parts of that article put the whole paragraph in as what you quoted is very very misleading. what the whole post said is

"Dolomite, as you know, contians both calcium and magnesium carbonate. I don't really see a big problem with it, but maybe a little one. It's possible that as it slowly dissolves, the magnesium level may rise, and you might want to take a measurement of the magnesium once in a while to make sure it isn't rising too high.

I'd expect that routine water changes would keep it in check, and a big one would certainly correct it if for some reason the sand were dissolving fairly fast."

also one more thing if you check into all thoes posts on RC (I have) 90% of them are talking about dolomite gravel (large stuff). now weather this makes a difference or not.. I don't know.

Steve

DJ88 · #27 01-24-2002, 01:56 AM

As a bit to add:

I was reading through Fishnets library and came across this from the Advanced Aquarist forum;

<blockquote>quote

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The level of magnesium will determine if your solution will form aragonite or calcite. Corals and shellfish generally only form aragonite. If you are looking for maximum biological calcification you must not have excess magnesium.

As well Andrew brought this to my attention;

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Mg++ allows Ca++ to go up but if it goes up beyond a reasonable ratio it will cause alkalinity to drop -- you know the whole Ca++ Alk balance thing.

I looked it up and found reference to it on Fishnet during a discussion with Randy Holmes Farley about dosing Epson Salts to boost low Mg++ levels:

<blockquote>quote:<hr>

Bob –Given that Magnesium bonds tends to form on the xtals(crystals) of Calcium carbonate
thus inhibiting their dissolution, is it not possible that the reduction of
the total #s of CO3= in solution might decrease the pH?

Randy Holmes-Farley - Whether it did that on it own as MgCO3 precipitation (or something else like
Mg(OH)2), or on the surface of CaCO3, that is how I believe the pH would drop.
Of course, in the test I ran there was no solid surface of CaCO3, but in a
tank there would be.

Buffering effect would not be changed for any period as the SO4= would stand
in until the CO2 infusion would re balance.>>

I don't agree with that. The buffering (alkalinity) will be depleted. This
would be true whether you believe that hydroxide or carbonate or both were
removed from the system. Even after reequilibration with CO2, the solution is
permanently decreased in alkalinity, and will reequilibrate at a lower pH.

<hr></blockquote>

Just something else to consider.

Canadian · #28 01-24-2002, 02:00 AM

Do you know who Bob Goemans is? He's the "guru" of plenums. He argues that DSB don't work (or at least not as well as his mighty plenum). I hardly think that anything that Bob Goemans has to say regarding the efficacy of substrates pertains to a discussion about it's use as a substrate in a DSB. In addition, Bob Goemans completely discredits himself because his information is so slanted by his bias and desire to reap the rewards of payment from companies who supply him with products to "review" which, oddly enough, always seem to receive favorable reviews.

The art of quoting ideas is that you use quotes or paraphrase the ideas of people who are well respected peers within the particular area of expertise. Bob Goemans doesn't really fit any of these criteria. Sure he writes for a magazine, and sure he's written a couple of books, but I've got a book shelf full of text books with outdated or inaccurate information -- having your work published in publications which lack sufficient peer review can be done by any monkey with a type writer.

DJ88 · #29 01-24-2002, 02:18 AM

Steve,

Never heard of the stuff. But if you can get me more info I'll read about it. How is it's coating "breathable"?

In my readings about Dolomite on RC I found an interesting test done with Dolomite as a substrate and it's buffering ability. These are the results of a test done on three different substrates. It is done in salt water over a two month period. I found these results on RC. I do wish it had oolitic sand in its comaprison as well. But to me it illustrates that Dolomite isn't as good a buffer as has been made out.

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Laboratory experiments comparing the buffering capacity of crushed oyster shell (composed primarily of the most soluble forms of calcium carbonate -- high magnesium calcite and aragonite), crushed coral gravel, and dolomite sediments compared to that of silica sand. Of course silica sand had no buffering capacity and the tank pH dropped below 7.0 within 90 days. The other sediments didn't work so well, either -- after two months in a tank with a reasonable bioload, the pH of seawater in the tank with dolomite was 7.4-7.5, the crushed coral/aragonite was a little better at 7.7-7.8, and the oyster shell was the best at 7.8-7.9 -- again though, this was over only 2 months. In any case, none of them buffered the pH enough to rely on the capacity of the sediments alone to provide buffering over the long-term.

One more thing to concider. That fact coupled with the use of a Ca reactor, which tends to depress the Ph of a tank, may be of some concern.

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also one more thing if you check into all thoes posts on RC (I have) 90% of them are talking about dolomite gravel (large stuff). now weather this makes a difference or not.. I don't know.

If that is the case then there is less info on dolomite on the boards than I thought. If 90% are on gravel and not the small grain, then it is even more difficult to get the correct info is it not? More for a newbie to sift through and decode. How many people understand all the nuances of a DSB when they are brand new to this hobby? or what the current sciences are behind all the technical information available? not many. All the more reason to proceed with caution with regards to Dolomite as a substrate for someone new to the hobby.

Victor,
I say go on with your tank, all the power to you. [img]images/smiles/icon_biggrin.gif[/img] But I am still hesitant to say go for it to someone new.

[ 23 January 2002: Message edited by: DJ88 ]

DJ88 · #30 01-24-2002, 02:38 AM

Mg++ and problems with calcification of corals.

<blockquote>quote:<hr>By Ron Shimek:

Additional calcification reduction may be due to the substitution of strontium for calcium in the enzymatic pathways necessary for calcification. Strontium(and other doubly charged positive ions such as magnesium, barium and zinc) will occasionally substitute for calcium in the chemical processes that a coral uses for skeletogenesis. The substitution of strontium(Mg/Ba/Zn) for calcium by corals, mollusks, and fishes appears accidental (Sadovy and Severin, 1992). However, strontium(Mg/Ba/Zn) is not a twin of calcium and reacts somewhat differently than calcium, and may significantly slow down the calcification process. Thus, if the conditions are otherwise good for the corals, the addition of Strontium(Mg/Ba/Zn) would inhibit calcification.
<hr></blockquote>

[ 23 January 2002: Message edited by: DJ88 ]