New setup of 120 tank

  1. B

    BlackRev New Member Member

    I just setup my used tank and I did a water test today. PH is a 7.3 and ammonia, nitrate, and nitrite levels were at 0 even after 7 minutes. Are these acceptable levels? I haven't started to add fish yet. Trying to get the water temp up. I think my heater is not working, the light is on but the glass is cold when I touch it. The water is a little cloudy but I can deal with it till I can get a good cycle going. The tank has been filled for 4 days now.


    QQQUUUUAADDD Well Known Member Member

  3. jdhef

    jdhef Moderator Moderator Member

    Welcome to FishLore!

    It's good you found this site before adding fish! I highly recommend you read up on and fully undestand the nitrogen cycle (<--the words should be a link to an article) before adding any fish. It is the most important thing to understand when keeping fish.

    In a nutshell the nitrogen cycle goes like this:
    1. Fish produce waste which turns into ammonia
    2. Ammonia even at low levels are toxic to fish and will kill them.
    3. Over the course of several weeks with ammonia in the water a bacteria will start to grow in your filter media that consumes ammonia and releases nitrites.
    4. Nitrites even at low levels are highly toxic to fish and will kill them
    5. Over the course of several weeks with nitrtes in the water a second bacteria will start to grow in your filter media that consumes nitrites and releases nitrates.
    6. Nitrates at low levels are harmless to fish. But because in a cycled tank fish constantly produce ammonia and bacteria constantly converts that ammonia into nitrites and bacteria constantly converts nitrites into nitrates, your nitrates will keep getting higher and higher. You combat these rising nitrates thru weekly partail water changes.

    So since both ammonia and nitrites are toxic you need to protect your fish from those toxins. So basically there are two methods of cycling a tank so no fish are harmed.

    The first method would be fishless cycling, where you add an ammonia source to a tank that has not had fish added yet.This ammonia source simulates the ammonia the fish would be producing. There are several ammonia sources you can use such as pure ammonia/water solution (with no additives such as perfume, detergent, surfacants etc), a piece of shrimp placed into the water or even fish food. It will probably take 5 or 6 weeks for the tank to cycle fishless.

    Now the second way would be cycling "with fish". In this method you let the fish produce the ammonia that will allow the bacteria to grow. But because the ammonia and nitrites are toxic you need to do daily partial water changes of 35%-50% with a water conditioner that will detox ammonia and nitrites. One such water conditioner that is highly recommend is SeaChem Prime. The Prime has the ability to detox lowish levels of ammonia and nitrite for 24 hours, at which point you will be doing another water change with Prime. (In addition to giving you a vehicle for adding Prime, the daily partial water changes will keep the ammonia/nitrite levels low enough that the Prime can total detox them keeping your fish safe). This method will also take about 6 weeks.

    Now there is one other method of cycling with fish, and that is to use a product called Tetra SafeStart. SafeStart is basically a bottle of the bacteria that will grow naturally over time in your filter media. SafeStart has some very specific instructions. You need to fill you tank with water that was conditioned with a non detoxing water conditioner. Surprisingly Tetra recommend Tetra AquaSafe. Then wait a minimum of 24 hours and add your fish and an entire bottle of SafeStart. Then do nothing but feed your fish for the next 14 days (no water changes, adding chemical etc). On day 14 test your water and you should be fully cycled (i.e. 0ppm ammonia, 0ppm nitrite and more nitrate than what may be in your tap water).

    I also highly recommend getting a good liquid based test kit such as the API Master Test Kit. Stay away from test strip as the are notoriuos for giving bad readings.

    Good luck and feel free to ask any additional questions you may have. Fishkeeping in pretty non-intuitive in the beginning!