The Puffer Forum

I know RTR is a member here so I will use his literature.

My understanding from the article "Salt of the Earth, Salt of the Sea" is that as you add salt, you create osmotic stress on the bacteria (and fish for that matter). As you add more salt, you lose bacteria, up until you hit 1.010-1.012.

Here is the quote:

"Any salt added at and above specific gravity 1.010 -1.012 will kill FW nitrification bacteria. Smaller additions may do a partial wipe-out but not likely total unless done fast enough to osmotic shock the bacteria - which will osmotic shock the fish even quicker. If such additions are by table salt or pure NaCl, it will not support marine life of fish, inverts, and bacteria. Only marine mix (a very complex mixture of a large number of different chemicals) will do that. "Aquarium salt" will not support marine life, nor will table salt, rock salt, or sea salt."- Robert T. Ricketts

So what I am wondering is, does that mean a brackish tank has either very little freshwater (under 1.010) or very little saltwater bacteria (over 1.012) and is therefore going to have a very small biological culture, similar to how bacteria is less abundant in lower pH ecosystems?

I work at a store so I'm trying not to pass on any poor information and this is something that made me wonder.

Thanks a lot for the time!

i´m not very informed about bacteria types, but i can tell and ensure:
if there are brackish, marine, and freshwater complex-organism adapted and specialized to their own salinity conditions there are, consequently, Nitrosomonas, Nitrobacter & other bacteria adapted and specialized to their own salinity conditions.

That article makes reference to "killing FW bacteria" and to "killing SW bacteria", but not to kill ALL bacteria, killing all bacteria could be only possible if you rise salinity from 0 to 1.010 or marine, but anyway after 30 days of cycling the tank will be colonized by the corresponding bacteria.

What i mean is that BW is as stable as SW and FW if it is well done.

So basically, FW bacteria will die but a salinity tolerant bacteria will gow in its place and be just as efficient?

Is it the same species of bacteria, just an adapted version?

I think, according to what i´ve read, that the BW bacteria in our tanks (cuz we always jump from FW to BW) is FW bacteria adapted to higher salts concentrations, about the species i do not dare to say how or which are those who adapt, but this articles may explain how FW-BW-SW bacteria is found, but in a much bigger scale:

http://www.mendeley.com/research/bacter ... rn-baltic/

http://www.iopan.gda.pl/oceanologia/484cabaj.pdf

Anyway we should wait for the experts to talk lol

I'm sure that there is f/w bacteria which will endure to certain salinities, then marine bacteria takes over, I think. I don't think there is a middle type but I could be wrong. Rtr will be along soon to clear this up.

+1 to bertie's comments.

Stability is in the hands of the hobbyist. The earlier comment from RVS is to the point here: "What i mean is that BW is as stable as SW and FW if it is well done." If the hobbyist is careless and allows the salinity to fluctuate in the range from specific gravity ~1.008-1.014, the nitrification bugs may be damaged. That seems to be the transition range from FW to SW nitrification bacteria. There are lots of bacteria in the world, including lots of nitrification bacteria. But not all of those are capable of establishing long term in semi-closed systems (our fish tanks). Every species has a range in which it does best, and densities beyond which it dies not flourish. Specific gravities of 1.010-1.012 seem critical for long-term survival. FW types which establish long-term (indefinitely) do not do well beyond that range and similar SW forms seem not to do well below that range, so we need to be as accurate and careful as we can when we operate there. That means that we do not move through the slightly broader range from ~1.008 to ~1.014, where both types can and do live, but may or may not be fully stable. Do remember that specific gravity in the wild fluctuates with the tides and FW flow. It is a short-term fluctuation there and either or both types may well survive but not grow and divide while the salinity is unfavorable, but carry on normally when the local specific gravity is right for them. We do not have those twice-daily tidal fluctuations in our tanks.

Stable BW conditions are entirely under the control of the hobbyist. But even the most accurate hobbyists should allow sufficient adaptation time for the shift in predominant species of nitrification bacteria. Outside of the critical range for the nitrification bacterial species, Small specific gravity fluctuations (+/- 0.002) are relatively trivial.

FYI and somewhat related, high specific gravity at full marine levels (Red Sea densities, ~1.025) are harder on fish than minimal full marine conditions (~1.021). They have to work a lot harder to maintain their own internal osmolarity. So unless your specimens really need high density, lower density is not only cheaper, it is easier on and for most of the livestock.

Does that help? Make sense?

Perfectly for me.
Now, i have to realize that 1.010-1.012 salinity densities are not recommended for long term displays?
And that it is better to stay around ~1.008 to ~1.014 to avoid bacterial overexertion.

If you can keep it constantly within that range, it would be fine indefinitely. It is likely that the marine forms would dominate, but you cannot guarantee that.

The only issue with the transition range is if folks don't realize that there is such a thing and move through it too fast for the bacterial types to keep up with the metabolite load. "Stable" salinity is ideal, but outside that transition range the risk of minor fluctuations is small to most fish. Some inverts are more delicate.

Written in a way even I understand lol. Thanks rtr most informative.