Latest ph Profiles

Discussion in 'Carbon Dioxide (CO2)' started by Carpman, 10 Nov 2019 at 7:16 PM.

  1. Carpman

    Carpman Member

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    As I've been struggling with BBA, I decided to do a few profiles and here they are for you to peruse over. IF you can see any issues then please give me the heads up, I have taken a photo of all my notes with all the info needed. 20191110_190649[1].jpg

    20191110_190624[1].jpg
     
  2. freewolny

    freewolny Member

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    Tenfold increase/decrease of acidity over the day and massive water changes.
     
  3. dw1305

    dw1305 Expert

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    Hi all,
    I'm not, nor ever will be, a CO2 user, but I don't think you (or your fish) need to be concerned about the changes in pH from adding CO2.

    The same can't be said for a lot of snails, where pH below pH 7 will cause <"shell attrition">, and some fish (lake <"Tanganyika cichlids">?) may be a special case, due to the unusual stability and strange chemistry of Lake Tanganyika.

    When you add CO2 what changes is the CO2 ~ HCO3- ~ pH equilibrium point. This diurnal pH variation happens naturally in vegetated waters, as photosynthesis depletes the CO2 during the day and respiration depletes the oxygen outside of the photo-period. There are some references in <"TDS and remin......"> and <"pH variances....">.

    cheers Darrel
     
    Geoffrey Rea likes this.
  4. freewolny

    freewolny Member

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    I don't use CO2 either - I've ditched it (however I keep my CO2 system for experiments) because I think high amounts of easy accessible to plants CO2 in the water are completely unnatural and they dramatically increase metabolism of plants (not to mention high amounts of nutrients quite popular among hobbyists) which makes their life cycle shorter and they simply die quicker. Yes, plants don't live forever ind it's quite often overlooked by many hobbyists.

    Generally this topic with relation to the BBA requires longer writeup, and I'll do this later, but for now from another topic you've raised:

    Daily variations of the water parameters are rarely – if ever – taken into account. Data collected in a freshwater lake (Star Lake, VT) with a very low alkalinity showed a diurnal pH fluctuation beyond the imagination of most hobbyists. Thus, the pH at 10 am was measured at 5.7 (strongly acidic), 9.6 at noon (strongly alkaline), 8.3 at 2 pm (moderately alkaline) and finally, 6.4 at 4 pm (slightly / moderately acidic). Readings were taken at a 0.5M depth. The fluctuation observed was due to the low KH value of the water (something reported for the Amazon river, too) and the presence of large amounts of phytoplankton. Under the circumstance it is extremely difficult, if not impossible, to figure what is the “right” pH for any form of aquatic life collected in that lake and which tank could cope with this kind of fluctuation. The low – high points of the day differ by 4 pH points, which means that the concentration of H+ in the morning is 10.000 times higher than at noon, while this change takes place in just two hours. It goes without saying that this pH swing cannot be observed in an aquarium only because we cannot reproduce the amount of light which falls in the Lake. In any case, if somebody reported that a suitable pH for aquatic life collected in this lake should range daily from 5.7 – 9.6 most hobbyists would think it was a typo."

    Is this supposed to be a joke? Or Diana Walstad don't know how deep the Lake Tanganyika is? Most chichlids spend most of their entire life at the bottoms near the substrate on various depths of that lake, but definitely not at the surface - and those massive fluctuations occur at the top of the euphotic zone (wind, turbulences, phyto, high levels of light from the sun etc.). Unfortunately Diana created a myth about fluctuations being normal (implicating it's normal in whole volume of the L. Tanganyika and in our aquariums) which is followed by many hobbyists. And that myth needs to be buried deep down in our substrates - hopefully ammonia will kill it completely.
     
  5. freewolny

    freewolny Member

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    Aaargh... I've mentioned Tanganyika from the prev. topic while Ms. Walstad mentioned Star Lake - but rules are exactly the same.
     
  6. dw1305

    dw1305 Expert

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    Hi all,
    No, you honestly get large diurnal pH fluctuations in vegetated water, through-out the photic zone. If the water is very heavily carbonate buffered that reduces the amplitude of the variation, and shifts it entirely into the alkaline zone.
    Also have a look at <"A question......">.

    cheers Darrel
     

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