calcium, carbonate and dkh

[newdamsel]

Hi all

I have been using reef builder and calcium to perk the levels to 12dkh and 420 respectively. However accordingly calcium should be used in a 1:1 ratio in the tank, but it seems that for my tank, dkh can drop overnight from 12dkh to 9dkh, and every morning i have to prepare the reef builder solution and top it up. However what i notice is calcium level only drop minimally. So what is reacting with the carbonates?

I was wondering also if instead of adding calcium and carbonate separately, i use kalk. And if still carbonates is used up more than calcium, wouldnt that cause a ionic imbalance in the water (calcium ions accumulating over time)?

Do i have my concepts right? My pH is always at 8.2 if that helps.

[ep4546]

maybe u can use kalk to top up water to maintain your KH

[Achilles Tang]

Strange that your KH should drop so much like that while your PH remains constant.

Are you reading opposite? Usually PH is the one that fluctuates, a high KH should prop PH up. What is your calcium level?

[Tanzy]

dKH usually doesn't drop overnight by itself unless your tank is generating a lot of acids, especially nitrates. What's your nitrate level?

[newdamsel]

Oh ok, my pH is stable because I have another additive the pH buffer. Calcium is at 400 and nitrate is at about 20ppm. Alot of acids??? Hmm... could it be the bryopsis?? I have two bunch of them in the sump~! i switch off the sump lights at night~!!! could they be the culprits to use up the oxygen and generate lotsa carbon dioxide, thereby bring down the carbonate level? acid + co3 2- wouldnt that create even more co2??????!!!

[Tanzy]

The problem is not related to algae and carbon dioxide generated by livestock. It has to do with the calcium carbonate equilibrium in the water. Excess acids can upset this balance. Nitrates at 20ppm is not that high enough to cause the problem with dKH, but it can cause a massive algae outbreak.

CO2 + H2O = H2CO3 = (H+) + (HCO3-)

Excess acid (High H+ concentration) can shift the equilibrium left, causing a drop in hydrogen carbonate level and so decreasing dKH.

I'll suggest that you do a 50% water change and switch to dripping kalkwasser. Monitor closely and see what happens next.

[newdamsel]

Oh, gee doesnt that means that i have to throw away my ph buffer, reef builder and calcium additives???!!! gee.. wasted man... perhaps after i finish the carbonates firsts.. its running low anyway...

Hmm... but anyway thanx Tanzy and AT for your opinions~!

[lona]

Sorry..I'm a little slow at this.. ..but I still don't really understand, even after reading a little on the wetwebmedia site.

Newdamsel> Don't understand why you'll have to throw away your additives. If you're dosing with the calcium additives and a buffer as well, if done in moderation and with the usual measurement, why would that be harmful?

Tanzy> If too much acid is being produced, then how about removing the source? Maybe too many lifestock? Then stock less?

I'm still quite confused..all this is giving me a headache..

[lona]

ok could someone correct me if I'm wrong?

1. Dripping kalk adds alk and calcium in the same ratio. So for newdamsel's case, tanzy suggested a 50% water change is actually an attempt to 'push' the unbalanced water to a balanced water state, then dripping kalk to maintain this balanced state. It does not solve the problem, but observing what happens could be a reflection of the state of things in newdamsel's tank. If alk continues to drop, then as tanzy says, could be due to excess acidity from another source..(maybe too much livestock? too much decay? not sure here..would like some enlightenment.)

2. Newdamsel's action of adding bicarbonate to push up alk is correct, cos since everything else measures normal, dripping kalk in this state serves only to maintain the imbalance, and is not reccomended?

I'm really confused and could really use some enlightenment here...

[lona]

Oh and that also begs the question,

3. Why does using kalk mean that your levels will be good? Aren't calcium and carbonates used up at different rates? Using kalk maintains the calcium and pH, but you would still need to add carbonates to replenish their use too right? So might as well use the carbonates as well to maintain the pH?

[Tanzy]

lona,

1) and 2) are correct. At least it seems right after I skimmed(in a bit of a rush) it.

For 3), it's precisely because calcium and carbonates are used up at the same rate in a 1:1 ratio that makes kalkwasser for supplement. Kalkwasser, as you already know, tops up calcium and carbonate in a 1:1 ratio.

Usually it's just too high a bioload that causes excess acid. Nitrification end product is nitric acid which ionises to nitrates in the water.

Newdamsel,

No need to throw away the additives. Keep them airtight and away from moisture, they can be kept for a long long time. I still have all my buffers and what not to add to tank when I find a slight inbalance.

[wedgee]

Sorry if this sounds out of topic, but I am having slightly low dKH problems too, though they tend to drop only after a few days to ard 7 or 8...How come they dont drop lower than that?

And I'm having another problem too, my sand tends to stick together at some spots, and algae also binds to them in clumps...is this due to chemical imbalance too? I think i read somewhere b4 dat it is due to an excessive element, though i cant recall exactly wat causes this...

[lona]

Tanzy> Thanks for the reply. But on pointer 3, you mentioned that calcium and carbonates are used up at the same time, and kalk replaces the calcium and carbonate. That part I don't get, cos I thought kalk is calcium hydroxide, so where does the carbonate from kalk come from? Unless the OH- ions are pushing carbonates out from somewhere? *sigh*..my chemistry is SO rusty I tell you..

So anyways, I just tested my tank dkH, and it's at 8..so quite low. Should I continue to add the seachem marine buffer? Cos going by the pointers, I can either do a large water change then maintain with kalk as well, or would adding the buffer over the next few weeks be just as good since that would take care of the pH and alk just as good as well?

Wedgee> How do you tell if your sand is clumping if it's all on the bed? You're stirring up the sand or what?

[wedgee]

It rolls up into small balls with algae around some of them - when i break it up, it tends to 're-clump' in a day or two

[lona]

hmm..don't really know much about that..hope someone can enlighten you on that issue, should be quite interesting..

[newdamsel]

Tanzy> Thanks for the reply. But on pointer 3, you mentioned that calcium and carbonates are used up at the same time, and kalk replaces the calcium and carbonate. That part I don't get, cos I thought kalk is calcium hydroxide, so where does the carbonate from kalk come from? Unless the OH- ions are pushing carbonates out from somewhere? *sigh*..my chemistry is SO rusty I tell you..

So anyways, I just tested my tank dkH, and it's at 8..so quite low. Should I continue to add the seachem marine buffer? Cos going by the pointers, I can either do a large water change then maintain with kalk as well, or would adding the buffer over the next few weeks be just as good since that would take care of the pH and alk just as good as well?

Wedgee> How do you tell if your sand is clumping if it's all on the bed? You're stirring up the sand or what?

lona, i'm having a damsel, a clown and a dottyback in a 2x1x1 tank with a 2x1x1 sump, so i guess it isnt that much of overstocking i guess... but i think the cause would be the nitric acid which tanzy talked about coz my skimmer is still in the process of running in and maybe thats why such things happened...

same like you, the carbonate-kalk r/s is not clear to me too, how does kalk derives the carbonate in a 1:1 manner?? .... Tanzy can explain??

[lona]

Newdamsel> skimmer? how does the skimmer fit into all of this now? Thought the skimmer does not return any water to the tank? Unless it's leaking? Working principle should be to just foam the water only what right?

[newdamsel]

Newdamsel> skimmer? how does the skimmer fit into all of this now? Thought the skimmer does not return any water to the tank? Unless it's leaking? Working principle should be to just foam the water only what right?

Hmm... i said skimmer coz the skimmer isnt pulling out the excess organic nutrients in my tank.. so its like these nutrients are not removed for like a few days liow, and the accumulation of these organic nutrients breakdowns to ammonia, then to nitrite and thereby nitric acid... at least that is what i'm postulating for now for the origins of acids...

Skimmer needs to return water to the tank of coz~! Returns foamed cleaned water... else why foam a column of stagnant water? draw water from tank - foam the water- return back to tank... perhaps i misunderstood your post?

[lona]

heh..understood the skimmer working a little more in detail over the weekend.. ..my fault..you didn't misunderstand me.

I don't know too much about skimmers at the moment, still trying to learn more..but I think I understand what you mean by skimmer still running in.

How's your dkH so far? Mine still hasn't gone up. Already added the buffer twice, still not moving. Thinking maybe today want to change water already.

[newdamsel]

lona,

My dkh is about 12 for 2 days already coz i have been dripping reef builder everyday. To crop up your dkh, get reef builder, not reef buffer. Buffer only stabilises the pH value, carbonate is the thing you wanna add to increase your dkh.

If i dun drip for a single day, it will drop back to about 9... at this rate, my carbonate is gonna be finished real soon~!

[lona]

Newdamsel> just to confirm, the reef builder is the one that raises calcium correct?

[Cedric]

I think Reef builder rises carbonate

[newdamsel]

yes cedric is right, builder raises carbonates which can be measured from your dkh test kit. Not calcium. to add calcium, there is seachem calcium or you can add kalk.

[Tanzy]

Kalkwasser is Calcium hydroxide solution (CaOH)

CaOH in water = (Ca++) & (OH-)

CO2 + (OH-) = (HCO3-) This is not the real chemical reaction but a simplified form.

So as you can see, for one CaOH molecule you can get one Ca++ and one HCO3- ions, so kalkwasser replenishes Calcium and Alkalinity in a 1:1 ratio.

(HCO3-) = (CO3--) & (H+)

Calcium carbonate is CaCO3 which the corals use to form their skeleton, so calcium and alkalinity are also depleted in a 1:1 ratio.

[lona]

Newdamsel/Cedric> Thanks, I understand already.

Tanzy> I guess this is beside the point as long as carbonate is formed, but if I'm right shouldn't calcium hydroxide be Ca(OH)2?