CaCo3

[Cory]

I want to mix calcium chloride and sodium bicarbonate in a small container with water and dose the precipitation as my own diy purple up.

Is this ok? How much do i need for each? I dont want any leftover calcium chloride or bicarbonate that would raise alk and calcium.

Im worried the sodium chloride would increase in the tank. True?

 

[Randy Holmes-Farley Verified Community Expert]

It is OK if you want to do it. lol

Use the calculator below to match 1 meq/L to each 20 ppm calcium:

http://reef.diesyst.com/chemcalc/chem_calc3.html

Unless you toss the liquid and use only the solid, there will be residual Na+ and Cl- in solution, plus a small amount of either alk or calcium, which ever is in excess (you can never EXACTLY match them).

 

[Cory]

It is OK if you want to do it. lol

Use the calculator below to match 1 meq/L to each 20 ppm calcium:

http://reef.diesyst.com/chemcalc/chem_calc3.html

Unless you toss the liquid and use only the solid, there will be residual Na+ and Cl- in solution, plus a small amount of either alk or calcium, which ever is in excess (you can never EXACTLY match them).

Ok thanks! Its just ive been reading again, and it seems in a lot of areas po4 is controlled by precipitation. Theres lots of studies.

 

[jason2459]

Ok thanks! Its just ive been reading again, and it seems in a lot of areas po4 is controlled by precipitation. Theres lots of studies.

Precipitation of what? Can you link to those studies please?

 

[Cory]

Precipitation of what? Can you link to those studies please?

Calcium carbonate. Im sorry i cant remember the article key words. But lakes and in some seawater areas precipitation of calcium carbonate was responsible for 70-100% of phosphorus binding, preventing eutrophication.

This is probably why purple up works it lowers po4 for some and not others.. Just a guess.

 

[jason2459]

I can definitely say CaCO3 hasn't effected my PO4 one bit. I would love to read the reseach in that working in seawater even not near that efficiently.

I know PO4 can bind to Ca and many have issues with PO4 leaching from their rocks especially when PO4 levels in the saltwater lowers.

Many also say the CaCO3 dosing or coral snow dosing helps clear their water up correlating the CaCO3 as a floculate that can be filtered/skimmed out.

I have not noticed that myself but one thing I have noticed in dosing CaCO3 is an increase in coraline algae growth on my internal overflow which is a plastic. I'm guessing the CaCO3 is "sticking" to the overflow and the coraline likes the textured surface.

 

[jason2459]

And looking at this thread I've been dosing just to see what happens as the price was cheap since around April

https://www.reef2reef.com/threads/kz-coral-snow-chalk-caco3.242288/

 

[Cory]

Nice. I seem to remember something about a growing crystal of caca3 doing the po4 binding. Ive made a batch of precipitated caco3, im going to try and strain it through a coffee filter and use that after i rinse it with distilled water. Then ill dose it for fun.

 

[Cory]

It wont strain through a coffee filter so i thought its too risky to use, i just dumped in both ingriends. Ill buy some caco3 powder and try that.

 

[Randy Holmes-Farley Verified Community Expert]

I would just point out that if you add CaCO3 that is already precipitated, the only places available for phosphate precipitation is the existing surface of the solid particles, while if it is precipitating in the tank, one can get phosphate into the whole of the forming CaCO3, which could mean vastly higher effectiveness.

All you can get on a particle surface is a monolayer of phosphate (and even that won't form).

But how many possible monolayers might be in a 10 micron particle?

1 monolayer might be 0.001 microns thick.

So 10,000!

 

[jason2459]

Which could be contributed by dosing kalk at the localized point.

I was thinking of some kind of reactor to use kalk safely to bind PO4 through another discussion, however circular it became, on the other chemistry section.

 

[Cory]

I would just point out that if you add CaCO3 that is already precipitated, the only places available for phosphate precipitation is the existing surface of the solid particles, while if it is precipitating in the tank, one can get phosphate into the whole of the forming CaCO3, which could mean vastly higher effectiveness.

All you can get on a particle surface is a monolayer of phosphate (and even that won't form).

But how many possible monolayers might be in a 10 micron particle?

1 monolayer might be 0.001 microns thick.

So 10,000!

Thanks, that reminds me of one article i read where a eutrophic lakes phosphorus was controlled by precipitation.

 

[Cory]

Which could be contributed by dosing kalk at the localized point.

I was thinking of some kind of reactor to use kalk safely to bind PO4 through another discussion, however circular it became, on the other chemistry section.

That would be great, just not sure how with messing up the tanks chemistry

 

[jason2459]

That would be great, just not sure how with messing up the tanks chemistry

This was my silly idea. The proposed argument from someone else was that limewater is more efficient at binding to PO4 then GFO and just as efficient as LaCL3.

So, to the only thing keeping me going is the idea that the theory is there which I agree with. Its the proof that is needed now to allow calcium hydroxide to be used to bind enough phosphates to at least be equal to GFO in effectiveness.

Thinking about that reactor theory I mentioned before. Multiple stages and closed loop with the system. Would have to be large or very slow but couldn't be to slow.

First stage would be a chamber of supersaturated limewater that water is mixed through. So, vinegar would be continuously injected into that chamber as well as lime.

Effluent would need to be filtered out of impurities as the precipitated metals would still be in suspension as well as hopefully CaHPo4 Some filtering mechanism for the next stage. 1 micron assuming since the precipitation caused by lanthanum chloride can be filtered out.

The alkalinity would be high? A stage of mixing with muriatic acid.

Then heavy aeration chamber before entering back to the aquarium.

 

[Cory]

This was my silly idea. The proposed argument from someone else was that limewater is more efficient at binding to PO4 then GFO and just as efficient as LaCL3.

I guess the only way it could be done is by overdosing limewater, and making the tank foggy. However youd need to manage the drop in calcium, alk and magnesium. Not sure how this would be done, or if its even safe.

 

[jason2459]

I guess the only way it could be done is by overdosing limewater, and making the tank foggy. However youd need to manage the drop in calcium, alk and magnesium. Not sure how this would be done, or if its even safe.

Yeah, dosing would have to be balanced with it all.

Now if just precipitating CaCO3 is needed and can bind PO4 at the same time one could through in a couple 1000w heaters in one section to force some precipitation with out spiking alk/pH, mechanical filter and chiller in the next sections, and then dosing to balance things out.

Just brainstorming some terrible ideas as I don't see an efficient way to do use either Ca(OH)2 or CaCO3 in our tanks safely. It would be interesting if it could be done.

Texhnically it can be done. Like with calcium hydroxide we could get a double replacement neutralization
3 Ca(OH)2 + 2 H3Po4 = Ca3(Po4)2 + 6 H2O
Correct the chemistry if I'm wrong there.

And for CaCO3, I hate to keep refering to off site but there was so many GREAT discussions in some classic old posts like this one with Randy and Boomer.
Calcium Carbonate phosphate reaction?
http://www.reefcentral.com/forums/showthread.php?t=1734227

I learned a lot in their interactions back then. Very happy to have Randy on this site and still active in the online community!