Re: [RML] ionic strength, avoiding fish kills

Dave Wilson (aqua.green at bigpond.com)
Sun, 04 Dec 2005 09:11:00 +0930

Julie,
There is an explanation of how the blood regulatory mechanisms operate in
fish in the Stephen Spotte book "Captive Seawater Fishes, Science and
Technology" published 1992 by Wiley . It goes into great detail on how the
fish regulate their blood pH and external factors that affect the process.
There is about 20 pages of really big words that would require me to spend
several hours with a dictionary to make sense of it but I am sure the answer
to your questions will be in there. Spotte's book has excellent
explanations of fish osmoregulation processes and many other topics that
affect freshwater fish as well as marine fish. Looks like they need to
keep their blood pH between about 7.4 and 7.8 and use bicarbonate and non
bicarbonate buffers. The process is affected by water chemistry and
temperature. They eliminate hydrogen in ammonium to regulate blood pH,
maybe why ammonium hurts fish, it stuffs up blood pH.

His explanation on carbonate hardness and alkalinity is about 20 pages as
well. The book is about 950 pages long and will take a long time to read.

Cheers
Dave

On 4/12/05 3:34 AM, "Julie Zeppieri" <bowluvr at hotmail.com> wrote:

> Thanks, Gary. :-)
>
> The KH of the Rift Lake tanks is 13. That is what the buffer is designed
> for. Never measure the GH, but my guess it is also moderate-to-high from a
> read of the buffer's ingredients. In the Rift Lake tanks, ironically, I do
> not use any crushed coral or shell, just the buffer. I only use crushed
> coral/shell (and in small amounts) in my non-Rift tanks to keep the pH from
> bottoming out -- even with discus and Apistos, as I have had the pH drop to
> 2.8!! The Apistos in the tank did fine, but I tested it due to the fact that
> the clump of previously happy Java Moss had gone to brown mush. ;-) GH/KH
> in my non-Rift tanks is in the low/soft range generally (tho not overly so)
> unless I tweak it further. I rarely do this BTW, as soft is fine for my
> needs for the most part. Even the guppies and rainbows don't mind soft so
> long as pH is not low as well.
>
> The main point to all my questions and such is that I am really not trying
> to find out IF pH drops are dangerous (I know they are), but WHY they are.
> My friend asked the physiolgy behind this, and I guess the ion thing by
> itself just doesn't seem like the right answer. Perhaps a part of it, but
> there are just things it does not address.
>
> I guess my next move is to try and contact the "wet vet" we have here in
> Oregon (U of O, Hatfeild Marine Science Center, and Oregon Coast Aquarium
> affilated -- busy man!). Hopefully I will get a reply, or at least some
> literature links. If I get a full explanation on this I will forward it to
> the list. I was just hoping to do this "in house" since so many of you are
> in the habit of knowing such details usually. :-)
>
> Julie <'><
>
>
>> From: Gary Lange <rainbowfish4u2 at yahoo.com>
>> Reply-To: r_m_l at yahoogroups.com
>> To: r_m_l at yahoogroups.com
>> Subject: Re: [RML] ionic strength, avoiding fish kills
>> Date: 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 hotmail.com> 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. ;-)
>>
>> Thanks!