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Thread: Facts and Myths about Ph

  1. #1
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    Facts and Myths about Ph

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    Hi, fellas,

    I asked for permission and Mr Wright Huntley said it's okay for me to forward his APD post to this forum. It's about the facts and myths surrounding Ph. Recently, a friend gave me a Ph test pen and to my shock at first, I found the Ph of some of my tanks to be as high as 9.2. I'm sure the Ph pen was in proper calibration as I checked it against my other tanks and tap water. Anyway, the tank that was registering 9.2 Ph was holding a pair of Simp fulminantis, fish that supposedly prefer acidic water. Inspite of the high Ph, the Simp fulminantis was healthy and laying eggs. It seems to confirm what Mr Huntley wrote is true, that fish don't give a hoot about Ph. So those of you who think that your Ketapang leaves are doing magic to your fish, think again.

    Anyway, here's his post:

    The typical LFS approach to tank chemistry seems to have left us with a lot of folks here who get very, very exercised over a pH swing of a few points.

    Please relax.

    Fish and plants don't much care about pH, depite the popular mythology. [OTOH, I have some magical herbs that will increase your sexual performance, remarkably, if you do believe those pH myths! ;-)]

    pH kits are extremely high markup items at the LFS, and most books have been terribly inexact (even quite wrong) about the effects (or meaning) of pH. It is easy to see that dramatic color change and even beginners get a measurement accurate to a few tenths of a point. The real question is, "What does that reading really mean to my fish and plants?"

    My conclusion? Not very much. :-)

    I have been observing aquarium fish, up close and personal, for about a half century and was curious for at least a decade before that. I don't think fish can feel, smell or taste a pH change! Can you tell the pH of the water when you jump into a swimming pool? Is the burning in your eyes any different from too much chlorine or from too-high alkalinity? From my own observations, I suspect that fish can't really tell, either.

    I'm quite sure that there is no such thing as pH "shock." Water changes can cause *other* parameters to change, some of which kill fish, but the pH is a non-involved one, or only an indirect one.

    Sudden shift to higher pH can turn the equilibrium from harmless ammonium to deadly ammonia, if any is present. The killer is the ammonia. The excess of OH- ions just allows the ammonia to form. pH does tell us the excess OH- ions are there, but doesn't hurt the fish of its own properties. Neither do the OH- ions. [I know. Same thing!] Without any original ammonium, the fish tolerate the pH-change quite easily. Just-received fish are often victims of this effect, as the ammonium they released in shipping is converted to a deadly burst of ammonia by the new, higher-pH store water.

    I would guess that the vast bulk of "pH Shock" cases are osmotic shock, in which the fish are subjected to sudden drastic tds changes before their osmotic regulators can adjust. That can cause wicked cell damage, leading to illness or death. Soft and hard water often have very different pH. If that's the only thing you know how to measure, it's easy to blame the shock on the pH change and miss the real cause, entirely.

    Measuring pH is not a useless exercise, but the results need meaningful interpretation before they are worth anything.

    How many times have we seen someone dope a tank into a chemical soup with pH adjusters, Almond Tea, etc., and then complain that the pH-KH chart doesn't give them the right CO2 reading? The chart, and measuring the pH and KH, are quite useful, but *only* if the primary buffer is carbonate/bicarbonate. If you add a bunch of other stuff and dose with "Blackwater Extract" and other such snake-oils, or put peat in your filter, don't use pH and KH to try to measure your CO2 levels. OK? Weak humic acids from peat can work on pH just like the weak carbonic acid of CO2 dissolved in water. Don't confuse them.

    Super-acid pH can, in some species, probably cause blood alkalosis and sickness. This is why folks with very soft water learn to fear the "pH Crash" that happens as food decay products build up in tanks with nothing to buffer them to the alkaline side. I suspect the decay products are toxic and even more damaging than the low pH alone. This gave rise to a myth that nitrites are deadly at lower pH. Phooey! It has little or nothing to do with pH. It has more to do with sloppy fishkeeping, IMHO.

    I have bred fish in tanks at around pH=4, and have never seen any fish experience distress in a *clean* tank at pH even lower than that. If you have no outside factor that poisons the fish, my general experience is that most fish will tolerate any pH between 3.5 or 4 and over 10. I have never hurt any fish by water change that suddenly changed the overall pH by a factor of up to 3 points (for example, 6 to 9)* if no toxins are present and osmotic conditions are matched. The fish are completely unstressed!

    Ammonium (at well below detection levels of the LFS tests, BTW) will kill the fish as the ammonia is increased by over 50 times in the above example. The trick is to be sure the original ammonium is *absent* (or chemically neutralized). [That's why it is great advice to beginners to just keep the pH at or just above 7.]

    At the advanced level most folks keep tanks on this digest, that advice is pretty primitive. Yes, you can shock your fish with temperature change. You can really mess them up by suddenly switching them from high-tds hard to low-tds soft water. Plant cells can be similarly abused. Just because you learned to use a pH test kit, don't blame every bad happening on the pH or its change. IME, it rarely is the real cause, and is usually totally uninvolved.

    I have a nice pH "pen" and some tds meters. I bet I use the latter 50 times more often than I use the pH meter. I'm learning what is important, and what is not. My order of importance in most aquatic endeavors is (Relative)Temp., tds, GH (and its relation to tds), KH and pH (last).

    GH vs tds is important because monovalent ions like potassium and sodium are often lethal if not balanced by enough divalent ones like calcium and magnesium for good cell metabolism. [This gives rise to myths about plants or fish not being salt tolerant, even estuarine plants like Java moss and Java fern. :-)]

    Wright


    Loh K L

  2. #2
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    Ummm. Maybe this is a silly question, but I can't seem to figure out what tds stands for.
    Great article/letter, by the way. Interesting.
    -Molly Leonard

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    tds - total dissolved solids. For RO water, will zero.
    Zulkifli

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    It is an interesting tropic, but I think we should treat Wright's comment with care.

    I also have a friend who swear that his fish don't need filter, only a air pump will do. "What's so difficult about keep fish, I have been doing that for years", he said.

    How can he compare fish and human behaviour in water?

    Try posting his comment into a very popular forum and we will get a perfect storm.

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    Thank you, Mr Loh!!
    I like this article . Great writer. I agree on most of his point but just one..
    I think Human and Fish are different :wink: .
    I never compare a fish with a person,
    but in some cases, I may be wrong, who knows? ::: let me do a comparison with human and fish,,
    Prepare 2 glass of acidic water
    If I pour some amount of acidic water on your skin, you'll feel nothing and no hurt. but what if I ask you to drink the same amount , you may not die but I may, I'm not the doctor, so I don't know. But do you think all doctors know?
    What if you do the same to the fish? Unless you're that fish, else, how sure are you she is in no pain? Sorry, but I always ask myself this question.. .

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    interesting article....
    though there are doubts on the comparison between human and fishes....
    but i think the part on the pH affecting the ions in the water is rather scientifically logical....
    it might be the link on how does the pH really affects the fishes....
    then there are still others who swear by the importance of pH....including the keeping of arowanas...

    great point for discussion based on the experience on Mr Huntley

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    Wonder how you could test his ideas, though ... two tanks with different pHs are going to be different in other ways, usually - peat, CO2, KH, etc. It would be hard to set up a controlled experiment.

    PS Follow up to the original silly question: you can test for dissolved solids? I have a lot of test kits but I've never seem one of those before! Is it mostly a biology professor type tool, or do you know of hobbyists who test for that?
    -Molly Leonard

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    I do not know of any chemical test kit, but for tds people normally used an electronic tester similar to the pH electronic test pen. It will give the readings in ppm.
    Zulkifli

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    Re: Facts and Myths about Ph

    Quote Originally Posted by timebomb
    So those of you who think that your Ketapang leaves are doing magic to your fish, think again.
    My observation
    Most of my nothos are kept with ketapang leaves, so far none of these tanks are down with velvet. I had 2 nothos tank without ketapang and coincidentally velvet strikes them many times. After their recent recovery I introduce ketapang leaves to the tanks and the velvet problem didn’t return unlike the previous times.

    I have no idea if ketapang leave have any effect on breeding, but certainly have taken care of my velvet problem. If you guys had done research on velvet disease, one of the recommendations is to give the tank a blackout; this will prevent the velvet from growing and eventually die. The ketapang leaves darken the water and this is not an idea condition for velvet to take their foothold.

    Recently most of my Malayan shrimps were eaten by my nothos, I ran short of shrimps for incubating my non annual eggs. I replace the shrimps with a small piece of ketapang leave instead of shrimps and I achieve quite good results.

    3 weeks ago, Au brought me 3 tray fry and I added a small piece of ketapang leaves in each tray, the water turn really dark. For the first time more than 90% of the fry in the tray survive. There are about 30 fry in each small tray! I mean really small tray.

    I think adding ketapang leave is not all about lowering of ph, it should have some healing and antibacterial or fungus properties keeping the tank clean and ideal condition for the fish to leave in.

    Quote Originally Posted by Wright Huntley
    I'm quite sure that there is no such thing as pH "shock." Water changes can cause *other* parameters to change, some of which kill fish, but the pH is a non-involved one, or only an indirect one.
    I used to believe in acclimatizing fish when transferring them from tank to tank, however when I have too many fish to handle, I just transfer them without doing any anything. A lot of time I transfer fish from clear water to a tank with ketapang leave. Just imagine the ph difference and most of the fish survive such treatment.

    Regards,
    Gwee Sia Meng
    AKA 08742
    SAA 163
    Fish List

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    I've being keeping different freshwaters fishes for many years and I don't do any acclimatizing to the fishes I bought. Even at present moment, I just do 90% water change weekly to all my killifish using direct tap water. All my fish still survive and breeding. I think most of the problems arise from the water condition(bio-load) minus the PH factor. I don't measure the PH in my tanks.
    Au SL

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