# Nerite Snails in high tech



## EnderUK

I'm just wondering if it's possible to keep Nerites in a tank when you go sub pH 7 due to CO2. I know their shells start to get damaged when they're prolonged to acidic waters. If I'm adding CaSO will this prevent that or is this just going to lead to death.


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## Sacha

I've had a nerite in my high tech tank for over a year and it does ok. I wouldn't recommend it though. 

I have quite a lot of surface agitation, which drives the pH up above 7 overnight. The lights are only on from 3-10pm. So between about 11 pm and 11 am, the pH stays above 7. I never see the nerite in the middle of the photoperiod, but he comes out as soon as the co2 goes off.


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## tim

Does injecting co2 soften the water ? Surely if you have hard water to start with the nerite would fare better in the tank, the source water negating the effects of the co2 injection ? Interested as I have a few ramshorns that never seem to grow in my co2 injected tanks.


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## Sacha

No it doesn't. But the snails need two things- calcium and high pH. You can have as hard water as you like, but if you have made it acidic with co2, the snails will suffer. In acidic water, the calcium ions are stripped out of the shell of the snail


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## tim

So even though my waters acidic for approx 8 hours a day through co2 injection this would be enough to stop snail growth or inhibit their use of the calcium in the water ?


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## sciencefiction

tim said:


> So even though my waters acidic for approx 8 hours a day through co2 injection this would be enough to stop snail growth or inhibit their use of the calcium in the water ?



No, unless your ph drops in the range around 4 maximum 5. A ph of 6 and above should have little to no effect on the health of the snails as long as essential positive calcium ions are present/supplemented to the environment (Ca2+). Lack of Ca2+ in any ph will have a negative effect on them.

_"In freshwater habitats, snails appear more tolerant of low ph so long as sufficient Ca2 is available.
For example, Økland (1983) reported that at a given
pH high snail densities and species richness bothwere associated with
high environmental Ca2+. Such circumstantial evidence suggests that
direct uptake and use of environmental Ca2+ is important in persistence
of snails in acid-stressed habitats."
http://www.auburn.edu/academic/cosam/faculty/biology/feminella/lab/documents/Ewald_et_al.2009.pdf_

The Ca2+ are essential not just for snails but for all freshwater fish without exception regardless of their water requirement. Even discus and rams tend to suffer lack of essential ions related diseases such as HITH and similar as people tend to keep them in very soft water with very low mineral content that just can't keep up with the requirements of the enclosed Eco system and fish in it.


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## Sacha

Yeah...


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## Sacha

These are nerite snails. They are from brackish water. To thrive, they need a high pH with hard water. They will survive in acidic water, but their shells will become cracked and pitted over time


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## sciencefiction

Sacha said:


> They will survive in acidic water, but their shells will become cracked and pitted over time



If you bother to read further than the first sentence of your google search or at least bother to read the article I posted you'll will find out that the shells becoming decalcified is an attempt of the snail itself to extract Ca2+ from the CaCO3 of it's shell in an environment that is lacking Ca2+


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## sciencefiction

Sacha said:


> These are nerite snails. They are from brackish water. To thrive, they need a high pH with hard water.


Out of curiousity, I am presuming your tank water is soft and has low general hardness and carbonate hardness to start with? And you base your conclusions on personal experience?
The ph being lowered by CO2 does not matter. I can hardly believe it goes below 5?. More than likely your water just runs out of positive calcium ions either because they are not supplemented in the replacement water or not enough and big enough water changes are done to keep up with their depletion which is the case of all soft water keepers. Positive ions are not just used by fish or snails but they are subjected to a whole range of chemical processes.
In harder water which naturally provides more positive ions, or water not running out on positive ions,  with or without CO2 injection,  providing regular water changes are done as any tank needs replacement of positive ions, then this would have no effect on the snails.
The above article also states that the concentration of Ca2+ doesn't matter as long as there are some in the system. Yes, it doesn't specifically relates to nerite snails but it's the same logic as nutrients for plants, as long as none of the essential ones are at zero levels, plants grow regardless of the overall concentration. However, the concentrations themselves may have an impact on other chemical processes essential for the environment.


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## Sacha

Everything I have said in this thread is based on advice I have been given on this forum[DOUBLEPOST=1404561111][/DOUBLEPOST]http://www.ukaps.org/forum/threads/what-tds-should-i-aim-for.31049/#post-327053

"
"Also, have any of you kept Nerite snails happy in acidic water for a decent period of time..."


You can't, this is where both pH and carbonate buffering are important. Because the snail shell is calcium carbonate (in its aragonite form) it is a potential H+ ion acceptor, and if you place a shell into water with lots of H+ ions, they will rapidly erode the shell and kill the Nerite. A few snails are very efficient at extracting both calcium and carbonate from base poor environments, like Malaysian Trumpet Snails, and this allows them to grow in water that is slightly acid and calcium poor, but even in this ase the older whorls of the shell show erosion, and the MTS never grow very large. Red Ramshorn snails can also survive in water that is fairly calcium poor but neutral, as long as the pH doesn't spend too much time below pH7. "

http://www.ukaps.org/forum/threads/calcium-deficiency-white-snail-shells-shrimp.31687/#post-344420


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## sciencefiction

Sacha said:


> You can have as hard water as you like, but if you have made it acidic with co2, the snails will suffer.



My reply was to your statement above which is technically and practically incorrect.
As in regards to different calcium ion requirements for different snail species or fish, what's stopping one supplementing them one way or another? Why does one keep their system in a constant depleted state to start with? It's not good for anything at all.  They are the number 1 essential ions needed by any fish or invert living.


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## Sacha

As I said before, I was simply repeating what I had been said by Darrel. This is the advice he gave me: 

"Because the snail shell is calcium carbonate (in its aragonite form) it is a potential H+ ion acceptor, and if you place a shell into water with lots of H+ ions, they will rapidly erode the shell and kill the Nerite. A few snails are very efficient at extracting both calcium and carbonate from base poor environments, like Malaysian Trumpet Snails, and this allows them to grow in water that is slightly acid and calcium poor, but even in this ase the older whorls of the shell show erosion, and the MTS never grow very large. Red Ramshorn snails can also survive in water that is fairly calcium poor but neutral, as long as the pH doesn't spend too much time below pH7. "

Is this advice just incorrect then?


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## sciencefiction

Sacha said:


> As I said before, I was simply repeating what I had been said by Darrel. This is the advice he gave me:
> "Because the snail shell is calcium carbonate (in its aragonite form) it is a potential H+ ion acceptor, and if you place a shell into water with lots of H+ ions, they will rapidly erode the shell and kill the Nerite. A few snails are very efficient at extracting both calcium and carbonate from base poor environments, like Malaysian Trumpet Snails, and this allows them to grow in water that is slightly acid and calcium poor, but even in this ase the older whorls of the shell show erosion, and the MTS never grow very large. Red Ramshorn snails can also survive in water that is fairly calcium poor but neutral, as long as the pH doesn't spend too much time below pH7. "
> Is this advice just incorrect then?



No, it's not incorrect but relates to what happens at very low Ph levels. A Ph level of 6 and above should have no such devastating effect on snails as long as they do have positive calcium ions in the environment to counteract, buffer the acidosis. The Ph levels at which snails actually die are nearly the same as most fish we keep in aquariums with very few exceptions so one should keep in mind how low Ph one is talking about.

More info on what happens of Ph of 3-4. When they talk about elevated Ca2+ levels, they do not talk about in the environment, but accumulation in the snail/invert body itself by extraction from its own shell when subjected to environment without Ca2+.


_Elevated hemolymph Ca2+ following acid exposure may be
explained by dissolution of internal calcium sources. For freshwater

and terrestrial crustaceans, this source would be from the calcareous

carapace (Henry et al., 1981; Morgan and McMahon, 1982; Wood and
Rogano, 1986). In this case, increased proton concentrations solubilized
CaCO3, yielding Ca2+ and HCO3 ̄ , the latter of which could be used 
to buffer the hemolymph acidosis.
The freshwater bivalve, Anodonta
cygnea, exposed to acidic water showed increased hemolymph Ca2+
that apparently originated fromshell–mantle CaCO3, as environmental
calcium was eliminated as a possible Ca2+ source (Machado et al.,
1988). In that study, exposure to acidification (pH 3) for 12 days
resulted in a significant hemolymph acidosis and a doubling of
hemolymph Ca2+, which was attributable to solubilization of calcareous
microspherules in the mantle. In our study, internal decalcification
from shell CaCO3 stores also was the most likely mechanism
accounting for increased hemolymph Ca2+ 
_


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## EnderUK

wow nice discussion, sorry haven't gotten back to it till now, major upset with my re-scape in that my filter is leaking out water been trying to get it to stop all afternoon, looks like I need to get a new one tomorrow. I've rescape using lime free top soil so my TDS is now at 165 after first dosage of Mg and Ca (gotta love the water in yorkshire). I think I'll wait a few weeks and see what it settles out at and what my pH is before deciding. I know my old MTS do have shell erosion but that might of been from the time I wasn't dosing Ca. Much to think about thanks.


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## dw1305

Hi all,
I'm sure "sciencefiction" is correct, and that you can to some degree ameliorate the effect of very soft water by adding a calcium source that the molluscs can directly feed on. This could be something like cuttle "bone", or a dietary calcium source from feeding broccoli, or another green crucifer, but 





sciencefiction said:


> If you bother to read further than the first sentence of your google search or at least bother to read the article I posted you'll will find out that the shells becoming decalcified is an attempt of the snail itself to extract Ca2+ from the CaCO3 of it's shell in an environment that is lacking Ca2+


 I think that there are two processes happening, and we need to differentiate between them.

The first is at the mantle where shell production is occurring (in the "_extrapallial space_"), and here calcium may be re-absorbed into the haemolymph, as described in Ewald et al. (2009). This was a short term experiment which ran over 72 hours.

For the outer, older shell whorls, the pitting and shell loss is definitely due to H+ ions being exchanged for Ca++ ions. 
The mollusc can only regulate what is happening at the active site of shell formation, where it is laying down the organic matrix that will form the "shell scaffold" on which the CaCO3 is deposited. Once the shell is formed, and new shell has been built in front of it, it will behave in exactly the same way as any biogenic calcium carbonate and it will dissolve in acidic solutions. 

cheers Darrel


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## Rob P

I put 5 Nerites in my hi tech and lost 4 of them in not a very long time  I took the last one out and popped it in my slow tech Mini M to see if i could keep it alive and it's thriving well in there  

Moderately hard (Yorkshire) water here too 

I wouldn't put them in hi tech again but that's just because it didn't go well for me.


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## sciencefiction

dw1305 said:


> The first is at the mantle where shell production is occurring (in the "extrapallial space"), and here calcium may be re-absorbed into the haemolymph, as described in Ewald et al. (2009). This was a short term experiment which ran over 72 hours.



Yes, they explain that the snail extracts the Ca++ from it's own shell regardless of whether there is Ca++ in the environment or not when the Ph is very very acidic but this is a defensive mechanism of the snails.



dw1305 said:


> For the outer, older shell whorls, the pitting and shell loss is definitely due to H+ ions being exchanged for Ca++ ions.



The question I am wondering is why are the H+ exchanged for Ca++. Is that due to the reduction oxidation potential and isn't it just another indicator of lack of positive calcium ions and possibly even other reducers in the tank being exhausted out of the enviroment and can't keep up? Because in an environment where oxidation prevails, reducers will be exploited out of anything in the tank, it being a snail shell/Ca++ or Mg++. etc...whatever the oxidisers find around.[DOUBLEPOST=1404737385][/DOUBLEPOST]





Rob P said:


> I put 5 Nerites in my hi tech and lost 4 of them in not a very long time  I took the last one out and popped it in my slow tech Mini M to see if i could keep it alive and it's thriving well in there



CO2?....snails are sensitive and nerites can be even more sensitive than anything else to water quality for example.

I have a friend that keeps nerites in very soft water, ph of 6, no CO2 but a normal dose of liquid carbon daily and some ferts. Not a problem with them.


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## dw1305

Hi all,





sciencefiction said:


> The question I am wondering is why are the H+ exchanged for Ca++. Is that due to the reduction oxidation potential and isn't it just another indicator of lack of positive calcium ions and possibly even other reducers in the tank being exhausted out of the environment and can't keep up


Normally it is back to the CO2 ~ HCO3- equilibrium, so you don't actually lose any Ca++ ions, they just go into solution (although they may then form other insoluble compounds, for example if I added sulphuric acid (H2SO4) rather than HCl, insoluble CaSO4 will be precipitated). 

All acids are "H+ ion donors", and as you add H+ ions, the H2CO3 is formed (from CaCO3 going into solution). Any excess CO2 is evolved as gas.   

I'll use hydrochloric (HCl) as my acid, (but the process is the same for any H+ ion donor): HCl makes it simple to understand, because you can just ignore the chlorine ion (Cl-): 

You need "2H+" to make the equation balance due to the different valencies of the ions. (s = "solid", g = "gas", l = "liquid", aq = "in solution")

2H+(aq) + 2 Cl-(aq) + CaCO3(s) --> Ca++(aq) + 2 Cl-(aq) + H2O(l) + CO2(g)
discard the balanced chlorine ions and you get:

2 H+(aq) + CaCO3(s) --> Ca++(aq) + H2O(l) + CO2(g)

This is exactly the same process that happens when we add CO2 (or remove CO2) from water. If we add CO2, more HCO3- goes into solution from the CaCO3 "buffer" (in equilibrium with H2CO3), if we heat the water CO2 becomes less soluble as the temperature rises, and CaCO3 is deposited as "lime scale". 

CaCO3 is deposited because it is the less soluble  than the carbonates of the monovalent metals (K+, Na+). If we had lots of Mg++ ions in solution they would be deposited first, quickly followed by the Ca++ ions.  

cheers Darrel


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## sciencefiction

Thanks Darrel, very detailed as usual.
I understand the chemical reactions one by one but not as a whole picture inside the tank in addition to everything else. Are you saying that when you add CO2 all of the Ca++ are exhausted?


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## dw1305

Hi all,





sciencefiction said:


> I understand the chemical reactions one by one but not as a whole picture inside the tank in addition to everything else. Are you saying that when you add CO2 all of the Ca++ are exhausted?


 The calcium is still there, either combined into a (largely) insoluble compound (often CaCO3, but most calcium compounds aren't very soluble) or as an ion (Ca++). The carbon (C) is slightly different, it can be a solid (CaCO3), in solution (HCO3-, 2HCO3) or as a gas (CO2). 

The reason that calcium carbonate is such a useful compound for organisms (and has build up into huge biogenic rock layers over the last 3 billion years) is really the equilibria between CO2 ~ HCO3 ~ CaCO3.

The problem for the mollusc shell is that if you add an acid (H+ ion donor), CaCO3 will be converted into ions





dw1305 said:


> 2 H+(aq) + CaCO3(s) --> Ca++(aq) + H2O(l) + CO2(g)


 and even when the ions are re-deposited as insoluble CaCO3, they won't be re-deposited in the same place. 

This means that the older shell will degrade over time. 

The rate of degradation will depend upon the excess of H+ ions, and we can estimate this from the pH (the ratio of H+ ion donors : H+ ion acceptors), the lower the pH ("greater the excess of H+ ion donors") the more quickly the shells will degrade. 

If you always have an excess of H+ ion acceptors, ("base-rich" conditions like Lake Tanganyika) the calcium carbonate will never dissolve and huge _Neothauma_ shell beds (below), can develop



 
<http://seaframes.wordpress.com/2012/07/16/home-shelly-home/>.

The problem for us is if we take a mollusc which has evolved in hard alkaline water and place it in soft water it won't have any of the physiological adaptations to softer water. This is why you get a limited number of slow growing molluscs in acid waters.

cheers Darrel


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## sciencefiction

dw1305 said:


> If you always have an excess of H+ ion acceptors,



Aren't there more H+ acceptors in a fish tank?  Why would the H+ always go for the CaCO3 only and not lets say for some other base if available and thus spread the load of the acid conditions?
As I mentioned on another thread my snails had eroded snail shells in a Gh of 14, no co2 added at all, but no water changes for a while done and it seems to me the Ca++ were all exhausted and not in the form of Ca++ anymore or despite my ph of 7.4 I had loads of H+ attacking the CaCO3 of the snails.


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## dw1305

Hi all,





sciencefiction said:


> Why would the H+ always go for the CaCO3 only and not lets say for some other base if available and thus spread the load of the acid conditions?


Chemistry doesn't really work like that, the solubility of ions is dependent upon their position on the periodic table and their valency. 

For example if you add enough sodium bicarbonate (Na2HCO3) to a solution containing Ca++ and HCO3- ions, you will always get CaCO3 precipitate out, because CaCO3 is much less soluble Na2HCO3. This is the <"common-ion effect">, and how ion exchange water softeners work.





sciencefiction said:


> As I mentioned on another thread my snails had eroded snail shells in a Gh of 14, no co2 added at all, but no water changes for a while done and it seems to me the Ca++ were all exhausted and not in the form of Ca++ anymore or despite my ph of 7.4


 I'd look at it another way, if you have shell erosion you know that you have times when the pH is below pH7, the shell erosion is the "smoking gun". 

Have a look at "Old Tank Syndrome" - <http://www.skepticalaquarist.com/bioacidification>.

cheers Darrel


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## sciencefiction

dw1305 said:


> I'd look at it another way, if you have shell erosion you know that you have times when the pH is below pH7, the shell erosion is the "smoking gun".



Mmm, and what causes the ph to go back up exactly when I test it? The Kh was never below 5, from original 8 so the ph did have enough buffers.


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## dw1305

Hi all,





sciencefiction said:


> Mmm, and what causes the ph to go back up exactly when I test it? The Kh was never below 5, from original 8 so the ph did have enough buffers.


You need to take whatever approach you are happiest with. A lot of successful aquarists are fanatical water testers, but personally I very rarely test any of the parameters in the tanks.

I just use visual clues to give me an idea of when to add fertiliser ("Duckweed Index") or clean the filter (reduced venturi bubbles), or add a bit more tap water (severe snail shell erosion, our tap water is about 17dKH and 500 microS) to my rain-water for water changes.

The reasons for this are that I'm a pretty lazy tank keeper and these are KISS solutions which I've arrived at over time, based upon both my experience as a tank keeper and my day job.

For me the 3 parameters I'm really interested in for any fish keeper are

"_Do you have plants_?" if they don't keep planted tanks, I try and persuade them that actively growing plants are the single factor that makes tank management and maintenance of water quality easier.
_"What  type of filtration do you have_? _and what filter material is in it?_" Again if they can have a "wet and dry trickle filter" I tell them that it is the gold standard, it is a simple and robust solution to biological filtration. If they have a canister filter I talk more about flow and oxygen.
_"Biochemical Oxygen Demand_" bit of a strange one, because you can't measure it, but this is what plants and filtration parameters are really all about, reducing BOD. At the most basic level a successful tank is one where the amount of dissolved oxygen in the water column always exceeds the BOD. Assuming you feed your fish, realistically everything else is froth.
I'm in an extremely privileged position in that I  have access to a lab with several 100K's of analytical kit in it, but even with that resource there are plenty of tank issues that wouldn't be detectable.

Your eyes can tell you more than any analytical kit ever will.

cheers Darrel


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## sciencefiction

But that's exactly my point, one can't rely on tests to show them the conditions in the tank as it seems whatever tests we use are just useless of giving you the big picture.
I tested only out of curiosity to see in what directions the stats change over period of time without water changes. I've never ever relied on tests to show me if the conditions in the tank are good for plants or fish but it doesn't stop me from testing to see what those commercial tests are happening to show for one or another reason.
The Gh went from 12 to 14. The Kh went down from 8 to 5. The Ph remained unaffected at 7.4 all the time.  Yet, with these stats I get eroded snail shells in just one out of 2 tanks treated the same way for a period of time.  However, the other unaffected tank has dolomite(CaMg(CO3)2) under the substrate which as far as I know dissolves very slowly.
In the problem tank all snails were affected, mts, ramshorns and pond snails to various degrees so it wasn't just one species. The substrate differs too, the affected tank has sand the unaffected soil capped with sand(dolomite and potassium chloride under the substrate)[DOUBLEPOST=1404826567][/DOUBLEPOST]





dw1305 said:


> Have a look at "Old Tank Syndrome" - <http://www.skepticalaquarist.com/bioacidification>.



I've read this one a couple of times before. I am aware of what happens, hence I've tried to monitor if it indeed happens when one neglects a tank. For the last year or so I specifically neglected tanks for the first time and in none of them the ph dropped or even moved one point, keeping in mind that my tap water is naturally hard so it would take longer for that to happen. The Kh does go down but very very slowly so yes, one day the ph may have dropped if I left the tanks longer like that but I think that unless one has very soft water, there's enough buffers even from fish food added so the effect is really not that easy to cause.

But the only time I had "old tank syndrome" was not in non-water change tank but in a fry tank with heavy water changes but heavy feedings several times daily. The ph plummeted down quicky and fish were visibly affected which was why I noticed.


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## frothhelmet

I tried keeping freshwater nerites (Theodoxus Fluviatilis) initially in ph 6.5-ish water, but the pitting in the shells from the acid water eventually kills them (takes a couple months). When I raised the Ph over 7 they stopped dying and started breeding.


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## andy-mu

dw1305 said:


> All acids are "H+ ion donors", and as you add H+ ions, the H2CO3 is formed (from CaCO3 going into solution). Any excess CO2 is evolved as gas.
> 
> I'll use hydrochloric (HCl) as my acid, (but the process is the same for any H+ ion donor): HCl makes it simple to understand, because you can just ignore the chlorine ion (Cl-):
> 
> You need "2H+" to make the equation balance due to the different valencies of the ions. (s = "solid", g = "gas", l = "liquid", aq = "in solution")
> 
> 2H+(aq) + 2 Cl-(aq) + CaCO3(s) --> Ca++(aq) + 2 Cl-(aq) + H2O(l) + CO2(g)
> discard the balanced chlorine ions and you get:
> 
> 2 H+(aq) + CaCO3(s) --> Ca++(aq) + H2O(l) + CO2(g)



Wooah. Waaayyy too heavy for me. Chemistry aint my thang. Think in layman terms Nerites aren't perhaps suited to C02 injected planted tanks 

Comprehensive as I_'m sure your reply is Darrell, I know when I'm out of my league. Chemistry for me gets as good as, add hydrogen peroxide to water with the filter off and you get loads of oxygen bubbles and kill BGA as a spot dose. Fun to watch and somebody told me it was okay to do it. Just as well people like you are here. _


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## dw1305

Hi all,





andy-mu said:


> Nerites aren't perhaps suited to C02 injected planted tanks


 I think that's probably the bottom line. 





andy-mu said:


> Wooah. Waaayyy too heavy for me


Get away with you, it isn't really chemistry. 

Once you start injecting CO2 etc. you need to understand what you are doing,  mainly because when things go wrong it allows you to have an educated guess how to put it right.

cheers Darrel

.


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## sciencefiction

Is it because of the CO2 being unbearable rather than the drop in Ph because I have a friend with a tank with a Ph ranging from 5.5 to 6 and unreadable Kh and the nerites have been perfectly happy.


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## Sacha

Is the answer simply that no- one knows?


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## dw1305

Hi all,





sciencefiction said:


> Is it because of the CO2 being unbearable rather than the drop in Ph because I have a friend with a tank with a Ph ranging from 5.5 to 6 and unreadable Kh and the nerites have been perfectly happy.


 I've never used CO2, so I can't pass comment on that bit, and they may be the readings his test kits give, but I'd be surprised if they are the actual tank water readings.

I think once you are below pH7 shell erosion will occur even if the snails are eating a calcium rich diet. The shell is made of biogenic "aragonite" CaCO3, so once you are below pH7 the shell is going to erode once it is away from the area of active shell growth, even in snails that can live in acidic water. Nerites have quite thick shells, so it may take some time for obvious shell erosion to occur. 

Because pH is a measure of the ratio of acids (H+ donors):bases(H+ ion acceptors), an acid pH of below neutral (pH7) indicates you have more H+ ion donors than acceptors.

At pH6 you have 10x more H+ ion donors and at pH5 x100. So anywhere below pH7 you have this situation: 





dw1305 said:


> The problem for the mollusc shell is that if you add an acid (H+ ion donor), CaCO3 will be converted in to ions:
> 2 H+(aq) + CaCO3(s) --> Ca++(aq) + H2O(l) + CO2(g)
> and even when the ions are re-deposited as insoluble CaCO3, they won't be re-deposited in the same place.


 And the same applies to 0dKH, carbonate will lost from the older bits of the mantle, we know this because of the HCO3- ~ CO2 equilibrium.

All the time the pH is below pH7 available insoluble sources of carbonate will be converted to bicarbonate ions (HCO3-), and this will continue until equilibrium is reached. As the shell goes into solution both pH and dKH will increase.  Even if the dKH/pH then rises due to the addition of a more soluble carbonate source (like NaHCO3) the CaCO3 won't be re-deposited on the shell.

As soon as the soluble NaHCO3 (as Na+ and HCO3-) is depleted we're back at 0dKH (there is no reserve of buffering in this case because NaHCO3 is highly soluble), and shell erosion will re-occur. 

cheers Darrel


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## Mick.Dk

- and this is why I have a separate tank for breading ramshorns - pH 7.5 - 8.0.
Most tanks at Tropica are run on pH around 6.8, but I'm a sworn believer of benefits from keeping ramshorns in a tank. As seen from this thread, the ramshorns don't thrive long-time, though, and need to be re-introduced !!
- You just can't bend the rules of chemistry, basically..........


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## andy-mu

As the rolling stones once sang.....You cant always get what you want.

I'm at the re-scape planning stage. I would like nerite's and Sulawesi shrimp. Aint gonna happen with the type of PH I'll be running.
I do plan on C02 injection, T5's. Hopefully do it right this time. Get the flow and distribution sorted.

I take it basically all snails will suffer in the C02 injected planted tank?


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## dw1305

Hi all, 





andy-mu said:


> I take it basically all snails will suffer in the C02 injected planted tank?


You'll need some-one who uses CO2 to give you a definitive answer. My suspicion would be that if your water was hard and alkaline (both dGH & dKH high) you wouldn't particularly have any problem in the short term, although older shell whorls will degrade. 

During CO2 injection the pH may fall below pH7, but you haven't actually changed the water chemistry, you've just added more CO2 and driven the HCO3-~CO2 equilibrium towards CO2 (really towards the small proportion of CO2 that has become carbonic acid H2CO3). As soon as you stop adding CO2 the pH will rise as the HCO3-~CO2 equilibrium reverts to atmospheric CO2 levels.

Shell erosion will still occur during the periods when you add CO2, but these will be no more than 12 hours and followed by a period of hard water when shell can be built. Away from the shell mantle, (where active shell formation is occurring) erosion will occur whilst the CO2 is on. 

cheers Darrel


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## tim

I've had a few hitch hike on plants etc, London tap water (hard water) co2 tanks they never last long, generally they just don't grow.


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## sciencefiction

dw1305 said:


> but I'd be surprised if they are the actual tank water readings.


The tests used are liquid tests JBL for Ph showing 5.5, API ph doesn't go below 6, shows 6(yellow on the chart)
KH for both 0-1.
Water coming out of the tap is naturally very soft, I am not doubting the tests by much but not tested with digital Ph meter.
Owner also has Malaysian trumpets in the tank too doing just fine.
Tank is low tech, no CO2 added.
Oh, and I forgot to mention, owner had an Apple snail who had shell erosion so it seems it may depend on snail species who does well in low ph and who doesn't. Snail was given away.
The nerites are a couple of zebra nerites, about 1-2 years old, still alive and no shell erosion whatsoever


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## dw1305

Hi all,





sciencefiction said:


> The nerites are a couple of zebra nerites, about 1-2 years old, still alive and no shell erosion whatsoever


Interesting, there is definitely something strange going on. 

I'm pretty sure that in one of the other "low tech" snail threads there are pictures of a healthy Zebra Nerite in a tank with CO2 injection. Hopefully some-one reading this thread will be the owner and be able to offer some more details.

cheers Darrel


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## Sacha

My nerite snail is healthy enough, but I only see him during the Co2- off period. It's about 3-4 years old, and has been in this tank happily for this time. The pH drops to around 6.2- 6.4, the KH is 2-3.


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## dw1305

Hi all,





Sacha said:


> My nerite snail is healthy enough, but I only see him during the Co2- off period.


 Does it crawl above the water line during CO2 injection? That could account for why it is still doing well.

cheers Darrel


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## Sacha

Yeah it does. It spends at least 50% of its life above the water line. Only comes back in when the Co2 is off. So, at least it "knows" that the Co2 isn't good for it.


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## dw1305

Hi all,





Sacha said:


> Yeah it does. It spends at least 50% of its life above the water line. Only comes back in when the Co2 is off. So, at least it "knows" that the Co2 isn't good for it.


 That would make sense, if the Nerite is only in the water during the times when pH is above pH7 it wouldn't suffer shell erosion etc.

cheers Darrel


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## f.lloyd.taylor

I have nerites multiplying like rabbits in a 40 U.S. Gallon high tech tank with pH 6.4-7. CO2 injected, two Kessil A160we full intensity 10 hours/day, 50% intensity/70 % color another 4 hours/day, densely planted with crappy white sand substrate, EI dosing. I can't give enough nerites away but they keep that tank and three more FW I have spotless. I am moving 8 hours away in 2 weeks and will sadly be breaking down all of my tanks and keeping as many nerites as I can. Oh, other parameters: KH 9 and pH in between 6.4 to 7.2. Charts don't give the correct CO2 concentration though, otherwise fish would be belly up with the CO2 concentrations they give.... DC stays lime green... GH is supplemented with Ca++ and Mg++.


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## Christos Ioannou

Nerites did OK for me as well with co2 injection. Until I had to treat hydra infestation with dog dewormer; gone as collateral damage.


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## ajm83

f.lloyd.taylor said:


> I have nerites multiplying like rabbits in a 40 U.S. Gallon high tech tank with pH 6.4-7. CO2 injected, two Kessil A160we full intensity 10 hours/day, 50% intensity/70 % color another 4 hours/day, densely planted with crappy white sand substrate, EI dosing. I can't give enough nerites away but they keep that tank and three more FW I have spotless. I am moving 8 hours away in 2 weeks and will sadly be breaking down all of my tanks and keeping as many nerites as I can. Oh, other parameters: KH 9 and pH in between 6.4 to 7.2. Charts don't give the correct CO2 concentration though, otherwise fish would be belly up with the CO2 concentrations they give.... DC stays lime green... GH is supplemented with Ca++ and Mg++.



Brackish water?


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## f.lloyd.taylor

Not at all. I wasn't trying to breed the things, it just sort of happened. Only thing that is out of whack param wise is TDS, which was ~500 when they were multiplying. Now down to 300ish. They are still small as of yet, so I do not know if they'll live or be stunted or not. I'll keep the post alive with updates, etc. just for the sake of it though. Anyone want some nerites? I have em by the handfuls in three different tanks now. They are not laying eggs anymore though, at least not where I can see them, but they tend to lay on leaves, and I have a semi jungle of amazon swords....


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