Trying To Understand Ph

Discussion in 'pH' started by Fredbetta86, Aug 6, 2017.

  1. Fredbetta86

    Fredbetta86Well Known MemberMember


    So I understand the basics of PH and how it plays a role in my tanks but I'm a little confused on something. Why is it that when somebody performs a water change it doesn't effect the PH? Like for example say I do a water change on my tank that is established and has a PH of 7.8 but my tap water is 8.2. So I do a 20% water change but the tank stays at that 7.8 PH. I don't get it..
  2. Caitlin86

    Caitlin86Well Known MemberMember

    I'm gonna quote an awesome thread that will explain PH, gh and kh.

  3. MikeRad89

    MikeRad89Well Known MemberMember

    That's a bit much to read. In short, the chemical composition as far as dissolved solids is exactly the same in water straight from the tap and that in the tank. Out of the tap water will contain gases that either raise or lower the pH. After sitting in the tank the gas gasses off and you're left with the "true" ph of the water.

  4. Caitlin86

    Caitlin86Well Known MemberMember

    I agree it is alot to read lol..but does contain alot if great information.
  5. OP

    Fredbetta86Well Known MemberMember

    Thank you very much. It is a lot to read but it's covers all the bases so I'm grateful for you quoting it thank you!

    That's really interesting and thank you for your info. So is there a line as far as like to much of a PH difference? For example a tank is 6.4 PH and you do a water change with 8.2 PH. Sorry just trying to understand.

    Last edited by a moderator: Aug 7, 2017
  6. MikeRad89

    MikeRad89Well Known MemberMember

    Dissolved gases wouldn't lead to that much of a discrepancy.

    Keep in mind when you're doing a water change you're working with ratios. A 20 percent water change with even a ph of 10 isn't going to effect a tank with a ph of 7 all that much.
  7. sfsamm

    sfsammWell Known MemberMember

    Phenomenal information for someone looking to understand why an experienced aquarist is always asking for kH and gH values when they are struggling with mystery deaths, constant diseases, fish acting strangely, or difficulty cycling a tank... It applies in many areas beyond that but many new aquarist want to throw a chemical in the tank to "fix" a problem rather than actually fixing the cause. Even if the post is a bit more informative than some will understand, at the least it is highlighted very well why someone that does understand is asking for those parameters.

    Thank you for sharing!
  8. OP

    Fredbetta86Well Known MemberMember

    Ok thank you. I really appreciate you replying to my post. Ive learned so much from you guys and my aquariums are benefiting because of it.
  9. clk89

    clk89Fishlore VIPMember

    I personally found it to be really informative, great job. :)
  10. OP

    Fredbetta86Well Known MemberMember

    I agree, there is so much misinformation out there, or lack there of.. I wish these big chain pet stores educated their employees a bit more or told them not to give advice if they aren't certain about it. I might care to much about my inhabitants but I feel if someone is going to take up the responsibility of keeping them, they can take the time to do the research.
  11. Coradee

    CoradeeModeratorModerator Member

  12. NavigatorBlack

    NavigatorBlackFishlore VIPMember

    I don't think the stores should have to educate us at any level. We have to educate ourselves. Nothing is too much to read, if you truly want to understand.

    I have no formal science background - a Grade 10 science class, and that's it. I've managed to figure this out well enough to do some good things with my aquariums.

    I see pH in aquariums as an easy to read indicator of the minerals in the water. When I was newer at this, I would do a once monthly 50% water change, after topping up many times to cover evaporation.
    Fish would die in the week after. The pH wouldn't change though.
    Once I started testing for hardness as well as pH, I understood what I was doing wrong, and shifted to 30% weekly. That's why I am very skeptical of hobbyists using API ammonia kits like they are all that matters, and only doing water changes when the readings tell them to.
    We aren't all reading the right thing.

    Once you start figuring out pH, hardness and such, you realize what a myth the old "as long as you stick to farm bred fish" statement is. It's the modern version of "a goldfish is fine in a bowl". You can start looking at how fish kidneys work, in their endless battle to balance water inside and outside a fish. It's interesting, and it explains a lot more than dropsy.
    Then you can look at the evolution of fish eggs, and how species from mineral poor habitats have eggs that use every mineral they can grab (a disaster in mineral rich water).
    Call me a nerd, but this really adds a lot of interest to the pastime. I have bred close to 200 species, many from water not like what comes out of my tap, and the research and preparation is a great learning experience. It's certainly stuff for those of us who move beyond one or two community tanks.
    But it never does any harm to learn about things you may never get around to using.
  13. oldsalt777Well Known MemberMember

    Hello Fred...

    Don't fret over the acidity or alkalinity of your tap water. It isn't a requirement for keeping a healthy, basic tank with fish from the local pet store. I suggest keeping hardy fish like Guppies, Platys, Danios and Rasboras for now. They'll tolerate most water conditions as long as you treat the water with a conditioner and change out most of it weekly.

  14. OP

    Fredbetta86Well Known MemberMember

    Thank you for your reply! So far so good, I keep learning more and more from you guys everyday. So glad I found this site!
  15. Caitlin86

    Caitlin86Well Known MemberMember

    This site is the bomb!!!!!!! :;bananahey:;banana1
  16. toolman

    toolmanWell Known MemberMember

    @Caitlin86, agree wholeheartedly I can learn loads here while helping further discussion and answering questions. On other sites much less discussion.
  17. OnTheFlyWell Known MemberMember

    Depends on the GH IMO. A 10% WC with my 8.3 PH water (very high GH) will move my 7.0 PH distilled/RO water tank a full PH point quickly.
  18. Sarcasm Included

    Sarcasm IncludedWell Known MemberMember

    8.3 - 7.0 = 1.3 * 10%= .13
    PH would change to 7.13 though buffers would alter the final outcome.
  19. OnTheFlyWell Known MemberMember

    That math looks good. My reality says something substantially different. I can throw a coffee cup of my water in 10G of RO water and move PH .13. I don't pretend to know exactly why. If I exceed about 10% with my well water my ram rank PH flies very high. My KH is not measurable with an API kit. I add 50 drops and stop wasting the kit. Anyway my point was your water does indeed matter. You can't make general statements without the risk of being wrong because you don't know somebody else's water.
  20. toolman

    toolmanWell Known MemberMember

    It's not about being right or wrong, it's about opinions and experiences. Nothing is 100% all the time, no one here is 100% right always or claims to be. Calling someone wrong or saying they don't know is a case in point, you may be right but your also wrong by not finding a better way to say so.

    Absolutely no one here tries to give incorrect information.

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