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PostPosted: Jul 27th, '15, 13:56 
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High nitrites (10-20 mg/l) cause “brown blood disease” in fish and can result in death (the fish will appear to be gasping for air at the surface and their blood will appear chocolate in color). Calcium chloride can be added to the system to reduce the nitrite level.

.


OK - so a quote from an old paper on AP.. but not the first time I have seen reference to CALCIUM CHLORIDE.. and I had asked previously "..and why is it so.."

Can anyone confirm the chemistry behind the use of Calcium Chloride, a seriously cheap and safe product, and suggest just how it could be applied to our small systems..

Nitrites is clearly the BIG issue for us and if it is practical to control NITRITES whilst cycling and once cycled, then this should be yelled from the AP Roof Tops.. :notworthy:

and then... when playing with a RAS type system without plants, and trying to reduce the NITRATES, is there something similar that can be used to convert those Nitrates to something more stable or less harmful..
eg.. ending with Sodium Chloride :oops: , surely cant be bad..

under RAS, we don't want Ammonia, and definitely not Nitrites, and can happily pass on Nitrates..

So, start with a pH of 6.3
Quote:
You should note that a small change in pH can have a profound effect on the amount of un-ionized ammonia. At 25°C and a pH of 7.0, only 0.40% of the total ammonia will be un-ionized. While at 25°C and a pH of 8.0, 3.83% of the total ammonia will be in the form of toxic, un-ionized ammonia.

Add Calcium Chloride to control the Nitrites, and add ?????? to stabilise the Nitrates and thus control the TAN..

The less the Nitrates, the fewer the water changes and the less the chance of upsetting the whole show by water changes.. KISS :notworthy:
..
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PostPosted: Jul 27th, '15, 14:22 
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There is a thread on this somewhere; we used to have a person with a bit of (possibly lot of) knowledge on chemistry. The only thing I really remember was the proportions added were different (something to do with burrowing blind mammals) :)
If I remember or am really bored I will try to find it. :)

Edit

Here you go (should have remembered this one better) viewtopic.php?f=1&t=2775&hilit=calcium+chloride


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PostPosted: Jul 27th, '15, 15:15 
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....people should be aware that calcium chloride will precipitate some carbonates out of the water as solid calcium carbonate....


so far an interesting read, but a small disappointment, as it seems to be only REPLACING Sodium Chloride.. :dontknow: and I was hoping for a alchemy-revelation on a magic process of REMOVING the Nitrites.. :think: ..
So it is saying the use of the CALCIUM is more a first aide thing for the fish.. buggar... not what I wanted to hear..

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There has been a lot of discussion lately about salt and nitrite. The general invalid assertion I am discussing is that with salt, fish can be kept alive indefinitely. I will attempt to add a little perspective to the subject.
First off, the koi has to pick up lost salts from its environment, as the koi has to maintain a balance of 0.9 % salt solution in its body fluids (this is the equivalent of 1.5 ounces salt per imp gallon). The koi will be continually losing salt by diffusion across the gill lamellae.


DIFFUSION


Diffusion occurs with a solute (in this case salt) migrating from a higher to a lower concentration in an attempt to equalize the concentration. Once equalization is achieved, diffusion ceases. In the case of the koi, diffusion ceases when the 0.9% internal concentration equals the outside ambient salt concentration. As the external salt concentration should never be more than 0.3% on a permanent basis, and even this high figure of 0.3% is contentious, It is easy to see that the koi is continually losing essential body salt. So, the koi must pick up salt/chloride, which it gets from background salt levels in the pond water. Again, diffusion occurs across the gill lamellae via special cells, called columnar cells.
These cells actively seek out chloride ions; they also work against the concentration gradient, depositing the chloride ions in the blood stream (i.e., from a low concentration to higher one).

The problem is that these cells although actively seek chloride ion’s, they are not that selective in what they pick up; hence, they will pick up NO2 (nitrite) ions. So, what do we do if we have nitrite ions present? We simply out-number the nitrite ions with chloride ions. The common statement about chloride ions competing with nitrite ions for entry to the gill whilst gets the point across, is perhaps a poor choice of words in this instance, as it implies that there is some direct conflict/ battle between the two ions taking place, the answer is far from being that complex, If we achieve a ten to one salt to nitrite ratio in the pond water, the gill still has a ten to one chance of picking up a nitrite ion, which will occur if one comes into range of these special columnar cells in the gill.
An explanation?
Imagine you have a bag with 100 balls and 50% represent nitrite ions and the other 50% chloride ions, you have a 50/50 chance of picking up either a nitrite or chloride ion. Imagine the same mixture, but now the bag has 99 chloride balls and only one nitrite ball, there is a one hundred to one probability of picking up a nitrite ion. Salt does nothing to alter the toxicity of nitrite, we as koi keepers, just lessen the impact of nitrite by out-numbering the NO2 ions with the addition of salt. The koi will still diffuse NO2 ions as they come into range of the gill columnar cells.

Nitrite Toxicity (how is nitrite toxic?)
If the nitrite ions enter the blood stream, it oxidizes the hemoglobin to form methemoglobin - methemoglobin is absolutely useless as an oxygen carrier. A hemoglobin molecule contains four sub-groups (haem- groups) also each haem- contains ferrous iron, which gives the blood its red color and is also responsible for carrying oxygen. Each hemoglobin molecule can carry a maximum of four oxygen molecules, or up to 70% of the amount of O2 held in simple solution in its environmental pond water at any given O2 saturation. When a hemoglobin molecule is exposed to nitrite, its ferrous iron is oxidized by the Nitrite to form ferric iron. This not only changes the bloods color from red to brown (brown blood disease), but it also alters the haemoglobin’s affinity for attracting oxygen and further is incapable of oxygen transport.
The hemoglobin molecule is now known as Methaemoglobin, and this is the prime explanation for the toxicity of Methaemoglobin. Once this happens, the hemoglobin molecule is finished, no amount of salt will repair this damage until it is de-selected by the spleen and recycled to form new haemoglobin, but replacement by the spleen and kidney has its own problems, because oxygen transport is now deficient – system’s which drive the spleen and kidney to replace haemoglobin will detect this deficiency in Haemoglobin/oxygen, and will go into overdrive producing extra hemoglobin to pull back the shortfall. The spleen/kidney cannot indefinitely produce excess hemoglobin if further nitrite poisoning persists.
As haemoglobin production resources are used up by continual over production of haemoglobin, the fish will soon die of anemia, indicated by pale pink gills.
Also, note that chloramine does the exact same thing to hemoglobin as nitrite (oxidizes it to form methemoglobin), which is a good a reason for not running low-level NO2 readings (No2 levels should be zero (un-measurable)).

Another Phenomena that will alter the bloods affinity for attracting O2 and the carrying mechanism of o2, are a very low or acidic pond water ph.
As an acidic environmental change in the blood chemistry is essentially the haemoglobin’s cue to off load newly acquired o2 into the body tissue and to acquire spent O2 in the form of CO2 carbon dioxide and H2CO3 carbonic acid for exchange at the gill.
The spent oxygen in the tissue forms carbon dioxide, which in turn dissolves into fluid in the tissue as carbonic acid, thus lowering the body fluid Ph at this point, which, is the cue for the haemoglobin to release to O2 and pick up the CO2. On arrival at the gill if the haemoglobin is not met by a slight rise in ph the haemoglobin will want to hang on to the CO2 and not exchange it for O2 to continue the cycle.

Why do koi die continually from nitrite poisoning?
The above explanation is why a higher chloride to nitrite ratio or at least as high as is safe and practical, demonstrates why It is believed a 10 to 1 ratio is at best better than nothing but less than adequate, as this concentration will be found in most domestic water supplies,
And why continual low level nitrite will have a detrimental effect on the long term health of the koi A 0.3% saline solution - is much easier on the fish short term. Also, it’s very important to get to the root of the problem to eliminate nitrite (or chloramine) in the pond. Otherwise, sooner or later you will pay the price with dead fish.


OK - head spins - read it again, once or ten times.. :support:
..
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PostPosted: Jul 27th, '15, 15:24 
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..
and it seems to say that only a fool would want to eliminate NITRITES, as this would stuff your "CYCLE" and you would then have no NITRITES and no bacteria and soon NO FISH.... :upset: ANYWAY.. :lol:

So next - NITRATES.. if we can ameliorate the effects of NITRITES and leave the cycle to take care of that, the next wind-mill to tilt at for Aquaculture, is removing NITRATES.. :oops:

Oh, I can hear the sigh - not again... sorry..

and, as for the original quote ""Calcium chloride can be added to the system to reduce the nitrite level."", I think that is actually incorrect..
..
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PostPosted: Jul 27th, '15, 17:24 
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"..and why is it so.."


I used to love watching this show when I was a kid.



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PostPosted: Jul 27th, '15, 19:48 
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BuiDoi wrote:
So next - NITRATES.. if we can ameliorate the effects of NITRITES and leave the cycle to take care of that, the next wind-mill to tilt at for Aquaculture, is removing NITRATES..
More plants... or less fish/feed.

Quote:
and, as for the original quote ""Calcium chloride can be added to the system to reduce the nitrite level."", I think that is actually incorrect..
Yep!... Still the same amount in the system, just less crossing the gill membrane and into the bloodstream of the fish.

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PostPosted: Jul 28th, '15, 09:09 
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The addition of the chloride ion is to reduce the effect of nitrite toxicity during cycling with fish.
Once cycled and assuming adequate DO and lack of stupidity regarding stocking and feeding levels and adequate biofiltration you should not see nitrites registered in your system, occasionally ammonia at very very low levels when you do not get the balancing act right. :)


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PostPosted: Jul 28th, '15, 10:08 
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Yea I didn't want to be pedantic but I was going to mention the correct term would be 'mitigate the effects if nitrites' rather than 'reduce nitrite level'


BuiDoi wrote:
So next - NITRATES.. if we can ameliorate the effects of NITRITES and leave the cycle to take care of that, the next wind-mill to tilt at for Aquaculture, is removing NITRATES..

In AP, as yabbies mentioned, we control nitrates with the addition of beds/plants or the lowering of feed input. But you mention aquaculture, this isn't an aquaculture forum but the answer to your question is in RAS this is the 'down side' to this fish farming method due to waste water discharge. The basics of commercial closed loop AQ is that they incorporate waste water treatment methodologies where solids are removed and biological denitrification processes are employed and nitrates stripping. Its all been around a long, long time. The obvious reason AP became popular is that it uses that waste water to grow plants giving you more bang for your buck.

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PostPosted: Aug 1st, '15, 11:15 
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Charlie wrote:
Yea I didn't want to be pedantic but I was going to mention the correct term would be 'mitigate the effects if nitrites' rather than 'reduce nitrite level'


On the contrary, Charlie, it IS a case of needing to be pedantic..
I think the word used was "reduced", when it likely meant to say "Reduced the harmful effect".. thus giving a completely wrong impression.. :cry:

It would still be GREAT to have a magic substance that can be used to cheaply and instantly REDUCE the nitrites by conversion to a safe and stable substance, much like adding HCL - a reasonably dangerous chemical (although stomach acid/ but can still blind you)- that can be used to lower the pH..

Quote:
The above explanation is why a higher chloride to nitrite ratio or at least as high as is safe and practical, demonstrates why It is believed that a 10 to 1 ratio is at best, better than nothing, but less than adequate


so I interpret this (being a NON CHEMIST), as saying that if a starting unsafe NITRITE level is say one PPM, then this requires a CHLORIDE content of 10PPM, raising a new question.. "If it is good, why don't we just do it as a prophylactic, all the time..? "
( my ignorant thinking being that IF something goes wrong then an Ammonia Spike is followed by a NITRITE spike..)
Now I know that MANY recommend the permanent use of Sea Salt, and then observe that SODIUM is not good in AP, whereas if I use Calcium Chloride, then by biggest issue seems to be Calcium Precipitation.. :headbang: and that would have to be a good thing considering the coral and marble that I keep in the system, anyway..



Quote:
The obvious reason AP became popular is that it uses that waste water to grow plants giving you more bang for your buck.


and then we walk a tight-rope of balances of what is good for the fish and also for the plants

BTW -- 10ppm .. does this equate to about 10gm/1000L or 0.01ppt

It seems desperately low if the AP-recommend Sodium Chloride level is 1 to 3 ppt..??

and BTW - do others have trouble with API test kits and interpreting the color of PURPLE..
I can not reliably differentiate between anything from anything over 2.. Grrrr! and I don't think I am color blind..
..
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PostPosted: Aug 1st, '15, 12:35 
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10:1 is nowhere near enough IMO, 1000:1 (1ppt) is 100 times better- ie the fish will be taking up 100X less NO2, or 300X less if you run salinity at 3ppt to get over any NO2 spikes. Any NO2 is bad for the fish, so you should try to minimise their exposure to it.

Yea, the purples aren't always easy to tell apart- so dilute 5:1 (1 part FT water, 4 parts zero NO2 rain or tap water) and run the test again.

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PostPosted: Aug 3rd, '15, 11:44 
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Gunagulla wrote:
10:1 is nowhere near enough IMO, 1000:1 (1ppt) is 100 times better- ie the fish will be taking up 100X less NO2, or 300X less if you run salinity at 3ppt to get over any NO2 spikes. Any NO2 is bad for the fish, so you should try to minimise their exposure to it.


Thanks GG.. I read those recommended concentrations and thought there was something massively wrong.. or the writer was massively conservative

I think someone made the comment that Calcium Chloride had two CL IONs where NaCl had one (Derrrr?) , so does one interpret that as suggesting that you might go for 1.5ppt rather than the 3..
I am assuming that it IS the concentration of CHLORIDE ions that is the relevant criteria..


Quote:
Yea, the purples aren't always easy to tell apart- so dilute 5:1 (1 part FT water, 4 parts zero NO2 rain or tap water) and run the test again.


Oh dear, and I read you saying that and then I forget the trick when I need it.. Oh to old brain aint what it used to be..
PAUSE
well I am a bit clearer on what aint happening..
Just tested..
Filtered-Water, 50%AP, 20%AP, and 10%AP.. :dontknow: - Yes - you guessed it..
No difference between them.. :upset:

PS - the only real reason for thinking CalciumChloride, is the calcium.. I sometimes added CaCO3, AND I have broken marble in the sump, so using CalciumChloride negates any need ??? for buffering
( Unless I am displaying my chemistry ignorance again..)
..
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PostPosted: May 18th, '17, 11:12 
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Gunagulla wrote:
10:1 is nowhere near enough IMO, 1000:1 (1ppt) is 100 times better- ie the fish will be taking up 100X less NO2, or 300X less if you run salinity at 3ppt to get over any NO2 spikes. Any NO2 is bad for the fish, so you should try to minimise their exposure to it.

Yea, the purples aren't always easy to tell apart- so dilute 5:1 (1 part FT water, 4 parts zero NO2 rain or tap water) and run the test again.

Yep I am having that difficulty right now. Panicking a bit trying to sort it out and not sure what to do. I have salted to 2ppt and as far as I can tell the fish don't seem too distressed. It's worrying me though.

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