Lets Talk About ~Reef Chemistry~

[mojoreef]

Hmmm. well for me Curt dripping kalk is purely for the addition of alk and cal. the percipatation of P is not really much and nothing I can really control either. as it relates to the sandbed, it is in a form of a solid attached to the sand particle or LR. it will stay that way until the bacteria unbind it and attach it to thier matrix. Its pretty hard to break the bacterial biofilm that the bacteria attaches itself to with out really removing the particle. But the syphoing is a good plan as you should get a bunch of rotting organics before they get taken up by algae.

Mike

 

[Curtswearing]

Thanks. It appears the phosphates bind very well to the aragonite sand. When I yank my DSB, it appears, they will go with it.

 

[plumber_bob]

Mike,
Where are the optimal levels for mag? I can't get mine above 1200. I've been using warner marine mag addictives, but I believe this is so diluted that it really isn't doing much. So, what is the next line of action I need to take?
Thanks,

 

[NaH2O]

Curt, good points about stirring up the sand and making a mess. The filter sock should pick up some of the precipitated phophates.


Most saltmixes combined with the demands of our systems means we need to supplement (in most cases). Since we learned carbonate is important and also keeping things in balance is important, then how do you know which supplements and in what combinations to use? Also, in regards to kalk....it is a good supplement, right? but isn't if you are only looking for it to precipitate phosphates?

Can someone go over the marble analogy for me?

I have a zillion articles I can stick in here....there are a lot on Chemistry. Here is one that correlates with my question:

How to select Calcium and Alkalinity Supplementation Scheme by Randy Holmes-Farley

 

[Curtswearing]

I can get the marble anology for you.

Marble Anology

 

[mojoreef]

Bob your mag is right in the zone for balanced at your salinity. The reason your having a hard time trying to get it higher is your Alk is to high.
Here is a quicky on how they relate. Alkalinity want to percipate with your calcium as soon as the two ions meet. Magnesium coats the alkalinity ions and thus wont allow the alk to percipatate with the calcium. What happens to alot of folks in the hobby is that they hit a wall at around 300cal and cant seem to get it up beyond that, the reason is usually that the mag is low and all the cal the person puts in is just being percipatated out. Looking at your chemistry bob your mag is close enough, your alk is to high and your cal is also a bit high. If it were me I would just let the cal and alk get used up until they reach the proper levels, then just maintain from thier.


Mike

 

[mojoreef]

). Since we learned carbonate is important and also keeping things in balance is important, then how do you know which supplements and in what combinations to use?

Well thier are alot of ways to go with in regards to that Nikki. the basic premise is just to replace wihat is being used up in the tank. So always test for what you need and then add accordingly. As per which suppliments, that becomes more of a personal choice. For me I drip kalk and use a calcium reactor, so the vast majority of my elements are replaced that way. I also try to keep a better eye on my magnesium (lol). Trace elements are real tough and really impossible to test for them all so I drop in a couple of doses of trace elements a couple times a year. As per what products???? I tend to try to stay with the highest grade elements I can find, so analytical grade, so far the only ones I have found are Warner Marines. Although ROWA products are now entering the US so might have to take a look thier to.

).Also, in regards to kalk....it is a good supplement, right? but isn't if you are only looking for it to precipitate phosphates?

Yea Kalk is a good suppliement for the addition of calcium and alkalinity. the percipatating of P is something you have no control over, but I wouldnt rely on it for taking care of P problems.

Mike

 

[tankgirl]

Mike, Did we already talk about how pH affects calcification?

 

[NaH2O]

TG - it was in the beginnings of being discussed....I think? lol

Oh man NIkki your making me good deep again, lol. your close on the concept but the outside sources such as refugium, and depressing PH doesnt really apply as you noted, but a good conclution. Hmm how do I explain this one with out sounding like an expert, lol
Ok the respiratory carbon dioxide (CO2) is turned into carbonic acid (H2CO3), which is in turn converted into bicarbonate (HCO3-) and carbonate (CO3--) ions. The enzyme responsible for the addition of water to carbon dioxide to form carbonic acid is carbonic anhydrase, which is present in high concentrations in corals. The cells also have special pumps that exchange one calcium ion (Ca2+), kicking it out of the cell for 2H+ ions, which it brings into the cell. Next, one of the two CO2 molecules we made earlier is going to diffuse out of the cell, where all the calcium is being moved to. Since all the protons are being removed from where the Ca2+ is moving to, the pH goes up. The area right next to the cell gets super saturated with Ca2+ that the cell keeps pumping out, and one Ca++ combines with that one CO2 molecule that diffused out. the result is the formation of the skeliton. the left over product is 2H+, which is taken back up by the cell to start the process all over again.
So a quick overview would be that the calcium is a product that the coral is trying to get rid of. with the use of carbonates the coral has figured out a method of doing so fairly easy, and the whole process helps the coral and its zoox get the extra co2 it needs for respiration. So having to much calcium causes the coral to use to much of its energy budjet to get rid of it, will you get better growth?? not much at all, but what you will do is stress the coral out.

I think I need a little help understanding this...depressed levels of pH will weaken alkalinity....so, how does this affect the calcification process? Also, phosphates inhibit calcification?

Sorry for getting off track, but TG - started my brain in a different direction again.

 

[Stircrazy]

Magnesium coats the alkalinity ions and thus wont allow the alk to percipatate with the calcium.

Mike

Mike, I always though the Mg coats the calcium carbonate (CaCO3) ions, creating a layer of magnesian calcite (Mg/CaCO3) with the effect of sealing off the calcium carbonate ion from any further growth and preventing it from becoming large enuf to percipatate out.

Steve

 

[NaH2O]

Apologies again for taking a step back to calcification....what role does Strontium play in calcification? Does it compete with calcium, and if so, in what way? I know some add strontium as a supplement, but didn't understand what role it plays.

 

[mojoreef]

TG/Nikki remember its also about the location of the low ph. in the case you quoted thats inside the cell and vacinity. Lower PH makes more soluable, remember the concept of the calcium reactor??
On P it binds the Cal prior to the calcification process thus making it not available.

Mike, I always though the Mg coats the calcium carbonate (CaCO3) ions, creating a layer of magnesian calcite (Mg/CaCO3) with the effect of sealing off the calcium carbonate ion from any further growth and preventing it from becoming large enuf to percipatate out.

Thier are two real ways that mag plays the game. One is what I think you are refering to. the magnesium is attrated to the ALREADY paired cal/carbonate. In this concept the mag is attracted to the carbonate as it is a sitting duck, so it begins to percipate onto it, After while a thin coating of Mg/CaCO3 (magnesian calcite) begins to form as magnesium pushes its way into the growing surface. Eventually, the surface contains a substantial amount of magnesium.
The second method is called ION pairing and that is where the magnesium ion pairs itself with the carbonate ion as I discribed above.

Mike

 

[mojoreef]

Oh man Nikki not stronium, lol. Stromium is really kind of an unknown. I have read alot of studies that said it was an important factor and have read even more that show it as worthless, even some that show how toxic it can be. So a hard conclution is tough.
Here is my take, to much stronium is toxic, that is a fact. Stronium is very close in look and composition to calcium, and I believe it is used in calcification the same way calcium is, the coral needs it out, so it percipates it. Thier are a few critters that use it, such as some gastropods, squid (i think) and some free floating organisms. but really Stronium is only present at around 5 or 6 ppm, so really no matter what not a real big player unless you have to much.

Mike

 

[NaH2O]

What is the best way to determine your system's consumption? Take a Ca and Alk reading wait several days and test again?

 

[mojoreef]

Pretty much, what ever the difference is for the couple of days you dont dose, is what the tanks demand is.

Mike

 

[reedman]

OK Mike,

How about the effect of long term elevated PH on the tank....say a PH of 8.4 rather than the typical target of 8.0?

Also, are there any reactions in the tank (not from additives) that would cause an elevated PH? I know that dosing Kalk increases it, as well as many of the Alk buffers. Any other items that can swing the PH quickly or cause an elevated level?

Do most people use Epsom salt for their Magnesium maintainance?

I know that Alk & Cal are the elements to watch the closest and be tested most often. How often, practically speaking, would a person need to test for Magnesium to prevent a depressed level (on a typical 75 - 150 gal SPS dominant tank)?

Thanks Bud!

 

[mojoreef]

Reed I personally dont know of any reactions that will increase Ph beyond photosynthesis. thier are lots that will decrease it though.

Do most people use Epsom salt for their Magnesium maintainance?

No epson salts are magnesium sulfate, most additivess are magnesium cloride. So you can use epson but you have to watch because you are adding sulfate at the same time. the cloride version is better. for mine problem it was rather large so I went with both to split the pain. others can to but do like a 10 to 2 ratio with the sulfate being the two.

I know that Alk & Cal are the elements to watch the closest and be tested most often. How often, practically speaking, would a person need to test for Magnesium to prevent a depressed level (on a typical 75 - 150 gal SPS dominant tank)?

Once a person sets up a good maintence schedule and is basically in cruise control for cal and alk they usually test alk and cal every month or so to back check, I would suggest doing mag at that same time.

MIke

 

[plumber_bob]

Mike,
Over in the Reef Calculators forum is there anyway you can update some of the links? Specifically Calcium Alkalinity. I was also wondering if you could add the formula you used for calculating my mag, cal and alk, with the measurement of my salinity?
Thanks,
Bobby

 

[mojoreef]

Bob I cant find the new locations yet for the calculators, but I will keep trying. On the formulas scroll back a page or so and you will see it.


Mike

 

[tankgirl]

How about this one?
http://www.kademani.com/reefchem.htm