Re: [RML] ionic strength, avoiding fish kills

Gary Lange (rainbowfish4u2 at
Thu, 1 Dec 2005 08:38:20 -0800 (PST)

Ok, so reading and answering questions on coffee break is not the best idea. <some> of the stuff he said made sense, other items didn't. I agree that going from high pH to low pH, even with pretty much the same ionic strength could zap your fish. I'm usually taking fish from someone with well water (400 ppm GH, lots of KH and who knows how many other ions, pH ~ 7.8 or higher) and moving it to my 125 ppm GH, 3 degrees (~ 54 ppm) KH and fairly low in ions, pH ~ 7. So most of the time I'm dealing with both effects. Like you, I have gone from low to high (ions/hardness or pH) w/o any problems too, fairly quickly, w/o any problems.

Have you ever measured the GH/KH of the water that you are keeping your Africans in? I would bet that the aragonite or crushed shell/coral has raised your GH & KH a fair amount and it's probably higher than you think. Bottom line, take home message though is don't go from high to low, quickly, do it slowly. Take a few hours or even overnight for really big differences. Dripping from the tank into the bucket with the new fish is the best way to accomplish this w/o too much hassle. Just keep a lid on those bows as they really get crazy in a bucket!

gary lange

Julie Zeppieri <bowluvr at> wrote:
So, then, Gary, does this mean that you agree with that forum-guy's
explanation of the physiological "whys" in which taking a fish from high pH
to low will likely kill it, but taking it from low to high will likely not
hurt it?? I don't really see how that works, myself.

Seems to me this does not take into account that the ionic content of the
water may be close to the same from the "higher" pH to the "lower" one --
such as when one goes from say a 7.1 down to 5.4. I can get a higher pH
water here in Portland w/out greatly altering either KH or GH, and I don't
ever use much more than just some crushed shell or aragonite to keep pH from
tanking (outside of Rift Lake tanks, at least). Don't use much NaCl either
unless a problem (eg: Velvet) calls for it. Granted, I don't have a way to
test ionic content, but my tests do show that my water is still considered
"soft" even at pHs above 7. And yet in the above scenario, I *can* kill a
fish by just dumping it into a 5.4 tank from out of a 7.1 tank, even a
species which can theoretically handle the 5.4 if acclimated slowly, and
despite the fact that it doesn't seem to me that the ionic content would be
that different.

However, when I "shoot the elevator to the top floor" by dumping Rift Lake
buffer into a tank that was previously at about 7.4-ish and relatively soft,
sending it up to KH 13 and pH 8.3 (and goodness knows what GH or ionic
content), and the fish don't even seem to notice, well, I must say I am
stumped by this "ionic is the cause" answer. If this IS the case, can you
explain it to me so I get it? 'Cause I don't.

Mebbee I is just thick inna head or sumpin' -- dunno. ;-)