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Nerite Snails in high tech

Sacha

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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.
 

Sacha

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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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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.
 

Sacha

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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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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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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.
 

Sacha

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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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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.
 

Sacha

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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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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+
 

EnderUK

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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.
 

dw1305

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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
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.
  1. 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.
  2. 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
 

Rob P

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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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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.

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]
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

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Hi all,
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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