Cycling Question

  1. K

    Karl New Member Member

    Ok, so i have a 36 Gallon bow front, low tech tank. I am running a aquaclear 70 filter and a fluval C4 filter. With lots of BIO....My question is i added the Dr Tim's bacteria and ammonia. I am watching the parameters (ammonia test and nitrite). When the cycle is done what percent of water change should i do? I seen a video where the woman said to do a 100% change...but that seems kinda drastic. Anyone else have any input on this?
  2. losthero

    losthero Valued Member Member

    Never do 100% because you will kill the bacterial colonies that you worked so hard to create.Do at most 30% water change between 3-4 weeks if it's your first water change. When you add new water use chlorinator and biology solutions.
  3. Sassonic

    Sassonic New Member Member

    That's not the way I cycle, but I can tell you this, I've never done a 100% water change except for if I had to cleanse a disease-infested tank. I am guessing the woman is operating under the assumption that the beneficial bacteria will be built-up in your filter and gravel/sand and therefore you can take out all the water to drop the nitrate level and fill up the tank again. But the cycle would then be interrupted so I don't see the point. I would do 30% water changes every other day for a week. Then wait another full week at least and then add a few fish and let the tank get established, and slowly add a few more over the period of two months. The tank will sustain life much better if you don't overcrowd it, especially early on...
  4. Kellye8498

    Kellye8498 Well Known Member Member

    I usually do a 75-80% change if nitrates are pretty high which they can be after an intense cycling process but if they aren't crazy I just change enough water to get them to 10 or less. If my nitrates are 20 I do a 50% change to get them down to 10 for example. Sometimes I take a bit more to get them lower than 10 because they will just keep building up. I don't see any need to ever do a 100% water change unless you're starting over or have something really bad in the tank.
  5. OP

    Karl New Member Member

    Thanks for the replies...i just started it a few days ago and added the ammonia which is high (right where it should be) I only do the water change though only after the nitrates climb and the cycle is complete right? I was thinking of a 40% water change unless something is whacky.
  6. JesseMoreira06

    JesseMoreira06 Well Known Member Member

    100% water change can be done but you'll most likely never need to, It won't kill your cycle, beneficial bacteria live in your media not the water. After I cycle my tanks I do about a 90% Water change before adding fish.

    once your tank is cycled meaning parameters are 0 ammonia 0 nitrITes and whatever amount of nitrates then you do your water change, it also depends on how high your nitrates are , if they end up at example 100ppm then a 80-90% Will be nessecary, you want your nitrates to be under 20ppm before adding fish.