deep snad bed?

[Bifferwine]

Team Randy.

 

[Alexander]

Dom i remember seeing pics of the old tank.... .not sure if it was with a dsb but holy crap it was crazy overloaded with growth. wasnt that the same tank that you had that MASSIVE colt coral that was practically growing out of the water?

 

[fatman]

This may be of some interest.

Chemistry and the Aquarium: Calcium By Randy Holmes-Farley

....Consequently, aragonite first becomes soluble in seawater when the pH drops below about 7.7 (this value might be more like 7.5-7.7 in reef tanks where the alkalinity is often higher than in seawater). That level is attained in some sand beds, and permits the dissolution of some of the sand.
The rate of dissolution is fairly low, however, because the rate of delivery and degradation of organics (or certain nitrogen compounds) deep enough in the sand to permit a pH drop is fairly low. The rate will, however, vary from tank to tank as the different ways of delivering organics to deeper parts of the sand will vary (diffusion; movement by organisms; death of organisms, etc). Note that the need to oxidize the organics in deeper parts of the sand to permit dissolution of the sand has nothing to do with the oxygenation of the sand. It has more to do with the fact that at near surface regions of the sand, the pH will be closer to that of the tank water by acid and base transfer from the water column, and you need to be deep enough to permit a lower pH to become established.

:bounce: I have no reason to believe Anthony Calfo is lying, nor do I believe Bob Fenner is lying about at what temperature aragonite starts dissolving. Nor do I doubt the thousands of people who openly have shared their experiences in this regard. I also do not think thousands of commercial growers would still be following their Calfo and Fenner's recommendations if they were wrong and you were right. I do know that the pH's given above are the pH's in which crushed coral (calcium carbonate dissolve) not aragonite. Aragonite dissolves at a higher pH as it is geometrically different from calcium carbonate. This is not new information and I fail to see why you feel a need to argue about it. Aragonite dissolves starts dissolving at a pH of 8.2 and dissolves faster at even lower pH's that are experienced in the deeper levels of a deep sand bed. Speculation as to why that pH is lower at depths is still ongoing. I do know that a deep sand bed fed no nutrients has a low pH at depths as does a deep sand bed fed nutrients. Am I saying Randy-Holmes Farley is wrong. No I am saying he speculates as do others. I believe he believes he is right, or at least at the time he wrote that article. I am sure his speculations were based upon his experiences and training and hopefully what he learned from others. It is the same way with other experts in the field. Some are pure researchers and some are mainly practicing commercial growers/aquarists with educations and professional experiences in the aquatic field. Would I believe a pure chemist over Randy-Holmes Farley as to when aragonite dissolves in sea water. That is very likely. I know also for a fact that I keep my display tank at a pH between 8.3 and 8.6 and my aragonite still dissolves and I have no fish in my display tank leaving large amounts of detritus and I have very high circulation but there is obviously no diffusion of oxygenated water to the bottom depths of my deep sand bed. The material you have posted is probably pretty old as it is obviously dated, and it is contrary to fact in some obvious ways. I have no reason to be lying about this and I doubt Reeffreak, Calfo or Fenner have reason to lie about it either. I do not believe we are wrong as the facts of the disappearing aragonite sand sorta speaks for it self. Also you must consider a good majority of the calcium is removed with frequent water changes. :^:
I have just gone to the site you posted the link to. It clearly repeatedly refers to calcium carbonate. Repeatedly, repeatedly, repeatedly it refers to calcium carbonate. That is what the article is about. The fact that at one point he mistakenly refers to aragonite as dissolving at the same pH as calcium carbonate is understandable as the whole rest of the article is about calcium carbonate. They have the same chemical formula but they do dissolve at different pH's in sea water. They are structurally different. Crushed coral is calcium carbonate and it does not dissolve at normal marine tank pH's. Tht article is also at least 6 years old. The information and books as well as my recent experiences are all much more current. Anthony's book is less than a year old. And the wet web and RC articles and threads are less tha two years old at most. Some might infer something from this.

 

[ccCapt]

I didn't even bother reading your whole reply. I got to the part where you still say....Aragonite dissolves starts dissolving at a pH of 8.2.

I showed a reference from a well known and published chemist, yet you still say otherwise. Should I believe someone who has published countless articles on aquarium reef chemistry, or some dude from Alaska who spews nonsense and gives no references to back it.

Sorry Fatman, you lost any credibility you may have have as far as I'm concerned.

 

[cumminz]

I read his whole post. go read it. It says that It clearly repeatedly refers to calcium carbonate. Repeatedly, repeatedly, repeatedly it refers to calcium carbonate. That is what the article is about. it is not about Aragonite. it also says that it is over 6 years old, which as You and i both know, Alot can happen in 6 years. Go read his post. Don't criticize him if you wont hear what he has to say.

 

[ccCapt]

I read his whole post. go read it. It says that It clearly repeatedly refers to calcium carbonate. Repeatedly, repeatedly, repeatedly it refers to calcium carbonate. That is what the article is about. it is not about Aragonite. it also says that it is over 6 years old, which as You and i both know, Alot can happen in 6 years. Go read his post. Don't criticize him if you wont hear what he has to say.

LOL Please do some research before running your mouth.
What is aragonite?
From Wikipedia, the free encyclopedia.
Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO3.
Massive deposits of oolitic aragonite are found on the seabed in the Bahamas.

Aragonite IS calcium carbonate.

 

[cumminz]

Again, straight from Fatmans post....The fact that at one point he mistakenly refers to aragonite as dissolving at the same pH as calcium carbonate is understandable as the whole rest of the article is about calcium carbonate. They have the same chemical formula but they do dissolve at different pH's in sea water. They are structurally different. Crushed coral is calcium carbonate and it does not dissolve at normal marine tank pH's..... they are made from the same thing, just structurally setup up different

 

[fatman]

LOL Please do some research before running your mouth.
What is aragonite?
From Wikipedia, the free encyclopedia.
Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO3.
Massive deposits of oolitic aragonite are found on the seabed in the Bahamas.

Aragonite IS calcium carbonate.

Some people expend great deals of energy trying to climb over a glass wall just to see what is on the other side.
Yes, aragonite and calcium carbonates are polymorphs. They dissolve at different pH's due to that fact. Calcium carbobate is not aragonite and aragonite is not calcium carbonate. They are different geometrically (differing crystalline structures). I do not know why Bahama oolitic aragonite deposits is now being discussed by you. Diamond and graphite are a pair of polymorphs, are you also going to say the are the same degree of hardness. Physical properties such as differing crystalline structure effect things such as hardness, and at what temp they melt or at what pH they dissolve. Calcium carbonate is not aragonite and aragonite is not calcium carbonate. Saying something is a carbonate mineral is not the same as saying it is calcium carbonate. For an exa,mple sodium bicarbonate is a carbonate but it is not calcium carbonate. Just as a diamond is madeof carbon as is graphite., but graphite is not a diamond. They are polymorphs.
If you can not be civil then you should limit this eduactional experience to PM's.

 

[cumminz]

I got Your back Fatman. You have given me some good help in the past and i agree with you brotha

 

[ccCapt]

This discussion is drifting way off track. I quoted a published article by a well known chemist, and you decided he used the wrong word and that he speculates.
For the sake of this discussion, let's forget about what pH aragonite dissolves and the different structures of the many forms of calcium carbonate.

This is the statement I question.
Aragonite sand only has a half life of about 8 to 12 months, so am putting a new bag of sand in my tank at least once every month to two months at most. It looks like it settles, but it actually dissolves.

So being 1/2 the sand will be gone in 12 months, if I buy a brand new 40 lbs bag of sand and let it sit in my basement, in 12 months I'll have 1/2 a bag? Or does it have to be in seawater and now the 1/2 life is affected by other circumstances? Will it be different if I put it in freshwater?

OK, for the sake of this discussion, say 20 lbs/month dissolves. Where does it go?
However, the calcium, strontium, cabonates and magnesium that make up the sand does enter the water mix so it is not lost, it is used by corals and coralline algae for growth.
That would be some massive growth in a month. But wait....
I have never heard anyone using a deep sand bed say the dissolving sand contributed to much acalcoum, carbonate, magmnesium or thorium to their systems.

Is it used by corals or does it not contribute to the system?

Where does it go? How about this statement?
Also you must consider a good majority of the calcium is removed with frequent water changes.

Now water changes are being done to LOWER calcium levels? Why bother adding calcium to any system when water changes are needed to get it out?

Let's stay on track fellas.

 

[RyanG]

THis is the most stupid arguement I have ever read.

ccCapt do you use a DSB? Two people with a lot of experience on this forum who both do have posted that their DSB disolved at a high rate, if you actually use one and are having this arguement that is one thing but why argue about something that you(assuming) dont use? IF YOU ARE GOING TO ARGUE WITH SOMEONE ABOUT THEIR POSTS AT LEAST HAVE THE COURESY TO READ THE WHOLE THING! Just my two cents.

 

[Rcpilot]

I don't add calcium to my system.

 

[Rcpilot]

THis is the most stupid arguement I have ever read.

ccCapt do you use a DSB? Two people with a lot of experience on this forum who both do have posted that their DSB disolved at a high rate, if you actually use one and are having this arguement that is one thing but why argue about something that you(assuming) dont use? IF YOU ARE GOING TO ARGUE WITH SOMEONE ABOUT THEIR POSTS AT LEAST HAVE THE COURESY TO READ THE WHOLE THING! Just my two cents.

You know what they say about arguing on the internet...............

You may have won the race, but it's still just the Special Olympics.

 

[fatman]

How about looking at this way. Calcite and aragonites are polymorphs of calcium carbonate. Calcium carbonate indicates only the chemical formula, not the structure, the hardness, the melting temperature or the Ph in which it dissolves. Calcite is the end result or the fully converted form that has become a calcium based carbonate that will change no further. Aragonite is an intermediate as it is not yet calcite, which it will eventually become as that is the geometrically stable version of a calcium based carbonate. They are not the same, all calcium based carbonates do not dissolve at the same pH as they are geometically different. If you bury aragonite it over time will become a calcite. A calcite does not turn into or revert back into an aragonite. This calcite is mined and sold as calcium carbonate not aragonite because it is not aragonite. Aragonite is mined as aragonite and sold as aragonite not calcite or calcium carbonate. So it is OK, theoretically, to say all aragonite is a calcium carbonate as it has the formual for calciunm carbonate, but all calcium carbonate is not aragonite. And different forms of calcium carbonate dissolve at different pHs in marine water.
One can also say a beer is a beer is a beer. But I would rather have a Corona than a Budweiser. They are both beers, they both contain ethanol (principally), but they definitely are very differentOne can say a pine tree ia a tree and say that an oak tree is a tree, but one has leave sand one has needles. They are not the same but they are both trees. No chemist should just blurt out like information for a set of differing structures as if they are the same. One should not genearlize and say two different things are the same when they are not.

 

[ccCapt]

Thank you for staying on topic Fatman. In general, I agree with your statements above. Now if you can explain, a little more in depth, exactly what you mean by the half life statement.
Surely there must be extenuating circumstances. A bag of sand won't dissolve on it own.
And can you please explain where all the dissovled materials go?

Again, thanks for staying on topic.

THis is the most stupid arguement I have ever read.
Ryan, sorry you feel that way. There is alot of good information in this thread.

 

[fatman]

I have provided you in PM's with quotes from Calfo where he specifically states that aragonite has a half life of approximately 18 to 24 months. I believe I even gave you the page number where his quotes could be found. I also told you where in his book you can read at what pH aragonite and crushed coral dissolves. I also told you that I am a busy person and I do not keep records on how often I add sand that I was just giving a best recollection account of needing to add sand regularly. A closer estimate of what I replace is probably an average of 10 pounds per month out of a total of approx 420. That would mean ten pounds last roughly 42 months. Or that the half life is 21 months. If it would make you happier I will keep records and let you know this time next year how much sand dissolved. I have no idea what your point is about a bag of salt in your basement. The half life phrase is not of my origin I suggest if you do not like that use of half life you take it up with Mr. Calfo. As far as where all the calcium and other elements and chemical compositions, what is your point. If some are used by corals, some are used by coralline, some is dissipated or some is run down the drain with the next water change. It either becomes part of the system and its inhabitants or it is exported. I do not do water changes to lower calcium. I do water changes because it is a part of good husbandry. The fact that some calcium is thrown out rather than stored in ever increasing polluted water is not an option I would choose. If I add new water that has a lower calcium level, yes some calcium is lost to water changes. If you would like to know there are 381,000ppm of calcium in CaribSea oolitic aragonite. I will, through simple math, save you the trouble of figuring out the amounts of calcium involved. That ppm concentration means 38.1 percent calcium (as 381,000 is 0.381 percent of 1,000,000). That would mean approximately 0.86 pounds of calcium per week is made available to the tanks system through the dissolving of aragonite sand. No, I do not have my tank sitting on a warehouse scale. I have no idea how much of that calcium is taken up by my systems coral, coralline or even through calcium carbonate precipitation, nor how much is lost through salt spray and salt creep, nor by my landlords carpet, and I have no idea how much is removed through water changes. I do not run a calcium generator and I am almost constantly trimming and fragging corals due to growth. I do up to fifty percent water changes weekly, with 25 percent being the minimum. Therefore I do throw away a lot of calcium and trace elements. I do not add calcium or alkalinity supplements to my RODI water before mixing my new water. Therefore I am also likely diluting my calcium with every water change on top of throwing some out with each change. I am not receiving any funding for research in this matter, and I have no intent to do the exacting measuring, and documentation that would be needed to sort all of this out in a fashion that will every one that is a doubter of deep sand beds that they work and that they dissolve.
I am done with this thread.

 

[fatman]

Ah shoot. I thought I was done.By half life of the aragonite sand I meant, and I assume Mr. Calfo meant, at the end of the half life time given (herein 24 months) that only half the sand would still remain in the solid form it was when it was introduced. Meaning in short it would last twice that long. Two half lifes equal one whole life. Therfore if you started out with 240 pounds and it had a half life of 24 months. Then the 120 pounds would no longer be in the same form in 24 months, meaning it would take 48 months for all of it to change form. So 240 pounds devided by 48 months would mean 5 pounds per month would change form. 5 pounds at 0.381 = 1.95 lbs per month devided by 30 days = .0635 pounds per day or x 7 days = 0.445 pounds per week. I can not argue with this math and I have no proof where it all goes. Nor can I explain God or many other things. Even most chemistry is just educated guessing, as we can not see the reactions between chemicals during chemical reactions, but we make educated assumptions based on other educated assumptions, which are further based on educated assumptions. Educated opinions, theories and scientific laws are really just opinions, less doubted opinions, and even less doubted opinions. There are always doubters and always believers.
Now I am done.

 

[Bifferwine]

I am done with this thread.

Thank god. How about the rest of you be done with it too, unless you have something new to contribute, instead of repeating the same thing over and over again.

For the record, my sand bed does not dissolve at any noticeable rate, and like Fatman, I have 400 to 500 lbs of sand in my tank. But I do not run a DSB in my main tank, so maybe that is the difference. I will also say that in my 55-gallon fuge, I do run a DSB of 6 to 8 inches, and I also do not notice any loss of sand in there. I do agree with the statement that aragonite dissolves with time, but it seems from all the quotes and references thrown out there, the exact pH at which it begins to dissolve and the rate at which it dissolves is debatable, and like everything else in this hobby, probably dependent on the individual tank.

 

[cumminz]

Well Said Guys

 

[Alexander]

You know what they say about arguing on the internet...............

You may have won the race, but it's still just the Special Olympics.

actually its arguing on the internet is like being in the special olympics, even if you win your still retarded.. but I know what you were going for there. and he you can get a good look at a t-bone by stickin your head up a butcher..... err. .... you can get a good look at a bull by ..... lol. sorry if you don't get that reference but it totally fit there.