Cycling- When You Already Have A Tank Set Up

Discussion in 'Aquarium Nitrogen Cycle' started by VeeCeeJay, May 23, 2018.

  1. VeeCeeJayNew MemberMember

    I have a 3.5gal tank. I am upgrading to a 20H. Can I use anything from the old tank to cycle the new one. The 3.5gal does not have a filter, but could I use the gravel or decorations or even some of the water???
    And how would I go about doing that? Before you cycle, you decorate it and hook up all the equipment, right? You cycle the tank exactly like you would want it but without the fish, right?
  2. mattgirl

    mattgirlFishlore VIPMember

    Since the 3.5 gallon doesn't have a filter it is possible that there is some bacteria living in/on the gravel and everything else in this tank and moving everything over to the 20 might help jump start the cycle. The amount of bacteria depends on how long you have had the 3.5 up and running and how you cleaned it while it was running.

    We actually need more information before we can advise you on what to do. Do you have fish in the 3.5? If yes, what kind? How long have you had this tank running?

    Just a friendly suggestion....
    I just saw your other thread. It would really help if your questions were kept in the same thread. That way we would all have the same information. I now see most of my questions were answered over there.
    Last edited: May 23, 2018
  3. OP

    VeeCeeJayNew MemberMember

    Yes there are fish in it. 3 neon tetras and an albino Cory. It’s been running since December. It is in desperate need of some cleaning, but I’ve been holding off because I didn’t want to kill bacteria I could use in the new tank.

  4. mattgirl

    mattgirlFishlore VIPMember

    You may as well take a chance and go ahead and move everything including the water over to the new tank. Even then there may not be enough bacteria to jump start the cycle but it might and it will put you one step closer to a cycle tank.

    Remove the fish from the 3.5 gallon while moving everything over to the 20.

    Are you going to run a filter on it? The new tank will never cycle if not.
  5. OP

    VeeCeeJayNew MemberMember

    Yes. I was thinking of doing a lava rock filter I saw on the kind of DIY. I’ll attach a link. Do you think that will be enough for my tank?

    Skip to 4:52
  6. mattgirl

    mattgirlFishlore VIPMember

    Someone that knows more about DIY filtration will have to answer that question.
  7. MommaLake

    MommaLakeWell Known MemberMember

    Yes it will be enough filtration as long as you don’t overstock your tank.
    Since you don’t have a cycled filter, I would not buy any new fish yet until your diy filter gets fully cycled.
    I have made these filters before and have followed King of DIY for about 2 years now. He really knows his stuff
  8. OP

    VeeCeeJayNew MemberMember

    I am worried about overstocking. My dad has a 40 long in storage. Maybe I’ll set that one up instead. Would the lava rock bottle filter work in a 40gal? Should I use a 1 liter bottle instead?
  9. MommaLake

    MommaLakeWell Known MemberMember

    So the thing with filtration is how much you need is very dependent on tank size and what you plan to keep in there. For example if you never bought more fish and just kept what you have now then yes the little bottle with lava rock and an air pump would work for the 40 also but you may end up with areas of the tank where the water doesn’t have enough flow.

    I assume you want more fish because of course we all do. So for a 40 I’d do either a bigger bottle or better (I think) have 2 of the small ones. That way you can have one on each side and not have “dead spots”.

    Another cheap way to help keep your tank clean between water changes is to get pothos and you could zip tie it to the air tube and hang the leaves outside the tank. It will keep nitrates down and the fish will enjoy swimming in the roots.

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