It seems not much has changed

[Steve_Warner]

Hi all,
I was browsing through this section again and started to compare the params listed in such threads as the Rio Negro with params from one of my scientific research journals. This was a comprehensive compilation study of the Amazon environment(all aspects) done with some figures/charts dating back to the late 60's-70's. The figures are right on target with the ones reported in the threads, which tells me that they have not varied much in what 200,000 years ;D It is very interesting to note that in the Negro thread, the pH was read at 3.9 and there were MANY FISH found in this water. The figures taken years ago were the same as the reported ones, low 4 pH and VERY LOW conductance levels.......BUT why weren't all the fish dead from a pH crash? Were they sick and diseased? Unhealthy? They were mosy likely THRIVING in those conditions! Naturally, slow-falling pH............Hmmmmm
Isn't it fun to unlock the secrets of the jungle! ;)

Steve

[barron]

Hi Steve

That is a good point.

I have been pondering this question, and for now, I can only come up with the diet plays a role in off-setting the ph.

What this source is, I do not know yet.

Barron :-\ ;)

[daninthesand]

I think we might compare the low pH in the wild to what that same pH might do to our tanks at such low conductivity. It's not the same thing. The tank is finite and can have huge pH swings with finite buffering.

In the wild however, we are talking eons of delicate balance that the forest, water, rain fall, fish etc. etc. have created. And even though it is not infinite, the grand scale of things makes pH crashes impossible. There is no doubt however that the Amazon is delicate and the hands of man can, unfortunately, alter things quickly with deforestation, polution etc. Similar disasters have happened in trout streams in Canada and US. Acid rain and all that.

A well know breeder once told me he had a Ph meter malfunction and read high. When he figured it out, the pH of the hatchery was down around 3. He had no fish losses. These are tough fish in some ways, but wimps in others!

just my .02 :)

Daniel

[Jason]

I prefer to run spawning tanks at low ph's only way I could do it effectively without the crashes is.

1 big tanks 40g plus
2 have all the breeder tanks on a central, (this also helps with the pairs that pair up and lay in your com tank, then go cold when you pull them)
4 run the biggest central trickle you can build, I doubt much nitrification takes place(one of my wild spawning tricks is to add straight amonia too the tank) it does help with the ph stability alot though.
5 drip water with your target parameters into the trickle sump.

my next breeder central filtere project I'm gonna do will have a hybrid trickle/algae filter, just to try something new.

[ChloroPhil]

The question I would raise is this: Why aren't the fish dead from osmotic shock? If the water is so low in electrolytes that there is almost no conductivity, what's keeping the fish's cells from rupturing from water absorption from trying to obtain chemical equalibrium with their surroundings?

The incredibly low pH and conductivity can be traced to the river's source...the Upper Amazon rainforest. The Amazon River itself originates in the Andes and as such has a higher disolved mineral content than the Orinoco or Negro, which originate within the rainforest itself. With small springs filtering through tons of leaf litter and silica sand the river enjoys some of the best natural filtration in the world. With such an incredibly stable origin the only pH swings to be found would be at the onset of the rainy season and at the end of the dry season. Even so, since the rivers start with small springs and rain-fed creeks additional rainfall should only increase the volume/flow of water. I'm willing to guess that the conductivity would be more affected than the pH level. The rainforest is a remarkably effective buffering system.

[Steve_Warner]

Hi all,
Bio, checkout this link in reference to your osmotic shock query.

http://www-heb.pac.dfo-mpo.gc.ca/congress/2000/extreme/extreme.pdf

See the works on Sodium and Chloride ions(and Phosphorus if I remember correctly) within the cells of the Amazonian fish(and others) and how it relates to aiding Oxygen & osmo-regulation. Incidentally, the Amazonian branches such as the Negro are known to have VERY LOW conductance levels, such as 9-10uS. The interesting part of this is that the DOMINANT cation most prevalent(in the Negro at least) among the major cations is Sodium, NOT Calcium(which is usually the dominant one in fresh waters), Magnesium or Potassium. <--------the source of this info can be obtained at a major university library or maybe your neighborhood one. I obtained the above info from a periodical work called "Amazonia-Key Environments" by K. Furch and W. J. Junk. Libraries are a wealth of knowledge, especially college and university ones for technical stuff!.....plus, it's fun to read and learn about our favorite pet's home, the great AMAZON!............Damn, I sound like Marlin Perkins in the "Wild Kingdom" intro ;D

Steve

[ChloroPhil]

Thanks Steve...I'll read that when I've got a few extra hours....:)

[Smokey]

All I can say is wow. Lots of "big" words ... hmmm now where did I leave my dictionary ?

More to learn .

Smokey