Should I Do A 100% Water Change? Question

Discussion in 'Freshwater Beginners' started by Tricia120, Jun 26, 2018.

  1. Tricia120

    Tricia120New MemberMember


    My 12 gallon tank has been up and running with fish and plants for a year now. Unfortunately our last rummy nose tetra died (due to our high nitrates most likely, we just added a pothos hoping we could bring the nitrAtes down) and now there are no fish in the tank. Here are our parameters:

    PH: 7.4
    Nitrites: 0ppm
    Ammonia: not quite 0 but definitely below .25ppm, there was a tiny twinge of green on my test
    NitrAtes: 80ppm

    Now that I have no fish left in the tank (just some plants and a few teeny snails that came in from the plants), I'm wondering if it's best to do a 100% water change to get rid of those nitrAtes and that small bit of ammonia. Or maybe just 75% with my gravel vacuum? Our tap water has 5ppm nitrAtes.

  2. Lagertha

    LagerthaValued MemberMember

    Nothing wrong with 100% water changes in my opinion and in the opinion of a lot of pro fish keepers.

    Keep your filter media/sponge wet and your cycle will be ok BUT without fish providing ammonia your cycle will die soon anyway unless you add an ammonia source.
  3. bryangar

    bryangarWell Known MemberMember

    I don’t see why not, it shouldn’t harm any of the plants. You can do either one you want.
  4. OP

    Tricia120New MemberMember

    Okay thanks! How long do you think it will be before my cycle dies? The rummy nose died yesterday. He shared the tank with two other tetras and a platy but they all died a month ago so it's only been the one tetra for a month.
  5. IHaveADogToo

    IHaveADogTooWell Known MemberMember

    The beneficial bacteria can starve to death without an ammonia source after only a couple days. At most. If you drop a little bit of fish food in the tank, the fish food will start to decay and release ammonia into the water, thus feeding the bacteria and keeping it alive. Or if you have some pure ammonia, you can add that to the tank instead. You get more control over ammonia levels with pure ammonia.
  6. OP

    Tricia120New MemberMember

    Gotcha, okay thanks guys this helped a lot!
  7. jdhef

    jdhefModeratorModerator Member

    In the future you may want to preform more frequent or larger partial water changes in order to keep the nitrate levels down. Ideally you want to keep nitrates under 20ppm at all time, but since you have nitrates in your tap water that may be a little difficult, but you should definitely keep nitrates under 40ppm.
  8. OP

    Tricia120New MemberMember

    Thanks jdhef! Yeah once we realized we had nitrates in the tap, we decided we needed to increase the frequency of our water changes. Looks like this will be our fresh start to start doing that.

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