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Afraid of EI because of the large weekly water changes?

Discussion in 'General Plant Topics' started by Tug, Jul 2, 2010.

  1. Tug

    Tug Lifetime Charter Member
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    I know this has been well thought out, but I really don't know what to say to someone with concerns about the change in pH after large water changes. What, when so many people think they are a bad idea, should I know about large water changes?

    I can't imagine the water changes that much after a week, but why is it alright? Really, I don't know. And, what about a 50% water change after a month, or six months :confused:
     
  2. Gerryd

    Gerryd Plant Guru Team
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    Tug,

    If you change 50% of volume weekly even after 1-2 weeks of startup the water chemistry will remain fairly stable.

    PH can changes for many reasons including c02 injection. So if my PH goes from 7.1 to 6.3 due to c02 within one hour, that is MANY times the normal rise and fall of most tanks or natural waters...yet the fish are fine... how would it be different if the tap were 7.4 and my tank at time of WC is 6.3 or so? Fish are fine with it....

    Unless you are using RO water or some other special mixing of water to strike a particular value the fish will not suffer much from PH swings.

    That is not to say to change from 7.0 to 4.0 either...within reasonable limits most fish are fine with PH CHANGES....

    It is hardness changes that will cause more issues...

    Also note that ammonia is much more toxic at higher PH ranges...that is why it can be an issue for tangy tanks or reefers with the higher ph requirements...
     
  3. Tug

    Tug Lifetime Charter Member
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    Bingo!
    This is great! Is it NH3 at the lower pH? I'll look it up.

    About KH. Would a drop of 3-4 dKH be stressful to fish and how does the tank water lose KH. For example my tap water is 3-4 dKH and after a week it is around 1 dKH, if memory serves me right. I haven't checked KH in a while. Thank you, again.

    :eek: I guess I answered one of my own questions.
     
    #3 Tug, Jul 2, 2010
    Last edited by a moderator: Jul 3, 2010
  4. csmith

    csmith Guest

    I may be way off, but I believe plants can use kH as a source of carbon?
     
  5. Tom Barr

    Tom Barr Founder
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    If they have not changed their water much in the last 6 months, might not be good, but measure the KH/GH, not pH.
    These are more relevant than pH.

    So if they have not done much changes........have them do a few 25% changes, say 2x a week, then go for a 50%.

    I do 80% on some tanks, pH moved 1 full unit, 5.8 and goes up to 6.8-7.0 within about 20 minutes.
    I have 320 Cardinals, shrimp, rare plecos etc. Altums also did well.

    So........

    But this type of simple question and honest response, that is a good question.
    We know a lot less than we often think, and such simpler questions often get us.
    The key is being honest and then go hunt down the answer.

    Regards,
    Tom Barr
     
  6. chad320

    chad320 Prolific Poster

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    What is that? Spam on a forum? Get a life.
     
  7. Gerryd

    Gerryd Plant Guru Team
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    I deleted the post and banned the user.

    This is the first spammer I have seen in a LONG time....kudos to Greg for a fine software implementation...
     
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