Lets Talk About ~Reef Chemistry~

[mojoreef]

Ok a sadistic few of you want to talk about reef chemistry, SOooo here is your moment in the sun, lol.
Lets cover what is needed, and how much, what methods are used and so on. Or Why do folks want thier calcium levels so high, when calcium actualy stops the coral from growing??? that ought to raise a few questions. How do corals use calcium and carbonate?? what interferes with these processes?? Why is it not a good idea to use kalk to percipatate phoshates?? Lots of questions, so have at her.


Mike

 

[Darrell]

good as a newbie ill be watching this tread everyday
Darrell

 

[cookiemn]

Just use the synthetic corals and you never have to worry about your reef chemistry. LOL

 

[NaH2O]

LOL, cookiemn!! For that matter, why not have an air tank with some toy fish hanging from strings, too

Alright, I'll bite.....Can we start with the precipitation of phosphates? Precipitation means a precipitate/solid is formed. Since it is a precipitate, it is going to settle - wherever...bottom, LR, etc. While it sits - the bacteria will want to break down the precipitate to get at the phosphates (because it is yummy)? So, it will eventually be released back?

 

[plumber_bob]

How about, why do we keep our calcium so high, when in fact it slows the growth of corals... That should be interesting.

 

[fishermann]

mike good topic and i don't have alot of answers to thquestions. i am using the warner calmax now 2 part a & b and have my mag levels where they should be and have seen a real pickup in my sps growth since getting the mag up. i am interested in your views on kalk which we have talked about in the past verses the 2 part warner. i am keeping my levels at normal seawater levels now and things seem happy. i am coming up on a year now sps stuff and am learning alot. i have had fish on and off since late 70's ,but this sps thing is another world, which i find quite fasanating. John

 

[plumber_bob]

How about, what if your having problems get the mag levels up?

 

[mojoreef]

LOL I thought Iwould stir it up a bit with those comments, hehhe.
Ok Nikki ladies first. Its a common belief that kalk should be used to percipatate Phosphates. and it does, but is that something we really want?? if you have inorganic phosphates in your tank you want them to get bound up by organics so you can skim them out and be done with. When you use kalk to percipatate it, you are basically forming a solid Calcium phosphate. calcium phosphate needs a surface to seed to or it dont work, normally in our tanks LR or sand are the donor. what ends up happing here is eventually bacteria will break the bond between the calcium and the phosphate and bind it to themselves. So for all that process you end up with percipatated calcium (which dont help the corals much) and phosphate back in cycle.

Mike

 

[mojoreef]

Hiya Bob
Yea this one is a little deeper and you have to go into how the coral calcification. Ok heres the short version. Calcium will actually inhibit the molecules in the coral tissue from growing. Since the coral polyp is always pumping in fresh SW the calcium concentration in the surrounding water is the same as it is inside the molecules of the coral. In order for the molecule to survive and multiply it must lower the concentration of calcium with in it. It does this by attaching the free calcium ion to its outer membrane and then secretes it out and forms the skeliton. So the calcium is a waste product in sence. the real player on growth is the carbonate and the reaction it has with CO2 the zoox releases.
So having any level of calcium in your water that is beyond normal balanced levels creates a huge energy loos the coral has to give up in order to free itself.

That make sence??


Mike

 

[mojoreef]

hey john it is a little bit different isnt it, lol. Kalk is basically the addition of calcium and carbonate, nothing more and nothing less. the 2 parters give you all the proper elements in a balanced form...if you need them all or not lol.

BOB number 2, lol Getting Mag up is a bear, trust me I just went through this. 9 pounds of epson salts and 3 gallons of magnesium cloride later I got it back up where it belongs. I will never let that happen again. If you are experencing that problem let me know the cal and alk levels and we can check it out.

Mike

 

[fishermann]

i got mine up using mikes advice, i used epsom [spelling] salts from the drug store. my tanks are a 60 and a 75. i mixed about 1/2 gal at a time and added salts until it was saturated and would not dissolve anymore, i think that was about 1/4 of the salt pfg. which looked like a milk half gal jug, it was rite aids store brand, this was ro/di water. i then took a salinty test after each dose and found the salinity to be up about 1 point to 1.026, so i did just one dose for the week in each tank and when i did my weekly water change, which is 5 gals each i mixed up salt water in about the 1.015 range i believe. anyway after the water change, both tanks were rite at 1.025, so i did another salt addition and went througth the same weekly water change thing. i ran into a situation withthe test kit. after the second dose of salts i had my cal. b part additive falling out of solution. i bought three more kits, a mag, a alk, a cal. all of them salifert , same as i was using already and everything was testing a nat. seawtr levels. the new kits tested the same except for the mag. the new kit said i had 1470 of mag and the old one said 1310, nat being 1290. i took three test with each kit old and new and kept coming up the same., so then i have had the honor of getting to bting it down again, which i have done and things are hunky dory. i am sure mike can add to this since he had to do the same.

 

[fishermann]

i see mike already has posted

 

[fishermann]

bob mine actually came up pretty easy and i did keep a close eye on my alk and calk levels which didn't seem to affected much with this procedure. mine wouild have went really smooth if i had had a good mag test kit, but then again i don't have the 10 th biggest ocean either.

 

[NaH2O]

hehehe...you may think I'm on another planet with this one (yeah yeah yeah...many of you think I already am)

CO2 builds up at night, thereby depressing pH. We drip kalk (in part) to help keep the pH from dropping....some run refugium lighting with marcos on opposite light cycles to keep CO2 from depressing pH. I thought I read somewhere that the build up of CO2 --> depressing pH --> allows Ca to be freed up (? on the chemical pathway) and deposited in the skeleton. Then, are we preventing the deposit of Ca on the skeleton by running refugiums (with macro algaes) and dripping kalk at night? Or am I way way off base? Maybe there isn't a correlation between the pH and the Ca?

 

[reedman]

OK Mike, I'll bite.

You say "if you have inorganic phosphates in your tank you want them to get bound up by organics so you can skim them out and be done with. "

I agree, but how do you get them to bind with organics so that we can remove them. It seems to me that in a closed system it is pretty difficult to remove items that want to bind with things in our tanks.

Also, what is the balance between the benefits and detriments of Kalk at night. We have established in the past that there are certainly benefits. On some tanks can they outway the negative of binding phosphates? I just don't want someone to get the wrong idea here about kalk (myself included) if that is not the "Complete picture".

It's tough to talk about pieces of the system since they all interact so closely.

How about using baking soda/washing soda to maintain/increase your Alk levels? Any thoughts on that one?

 

[tankgirl]

I wanna play, too!
All my best advice comes from Mike who told me;
1. Ca is just as available to corals at 420 ppm as it is at 475ppm.

2. the higher the salinity of your water the more Ca it can hold - so 35ppt salinity is pretty important for keeping your Ca levels in a good range.

3. Everything has to be in proportion because if one component is unusually high, it bumps other components out of the mix (Mikes marbles analogy).

Other stuff I've heard;
Unlike Ca, higher Alk levels (somehow) helps corals a bunch? How does that work?

 

[plumber_bob]

mike,
My Calcium levels are... 435
Alkalinity.......................4.15

 

[plumber_bob]

Oh Mike,
And my mag will never go over 1200

 

[mojoreef]

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.

Sorry if that one seems difficult, its a real tough one to explain, and I need a heck of alot more coffie now


Mike

 

[esmith]

WOW, that's a mouthful. I think it's too late Mike you're starting to sound like an expert .

So where is the optimal level of calcium then Mike? Isn't the levels in nature between 385 - 410? If this is so, wouldn't it be best for coral health and growth, to mimic this more closely rather than maintaining levels around 420 as I've seen most people recommend?

Eliyah