"oil slick" and bubbles?

  1. fallemnier Initiate Member

    Hi there, So my tank has barely finished the nitrogen cycle. however i still have .25 ammonia when i do my water changes every 3 days. I think this is because of the small size of my tank (7.5 gallons) i just changed my filter media (not the bio media) and added aquaclears ammonia remover. diddnt really seem to do anything.

    I have noticed a discoloration on the water surface and did some reasearch. the closest thing i could find was what some people called an oil slick. now i dont have an oil well in my substrate lol so what is this? Is it harmful? what should i do about it?

    I also get some bubbles on the water surface right by my HOB filter. I read these are caused by silicates is that true? I just recently lost my job so buying exensive products just to keep my tank looking good really isnt an option right now. However if the lives of the tank inhabitants are in danger then I MUST do something. The plants are included in that also.

    another side note. would more plants eat up that remaning bit of ammonia?
     
  2. catsma_97504 Fishlore Legend Member

    Welcome to Fishlore.

    Your tank is not fully cycled until there is no measurable ammonia or nitrite; and some nitrate. Using ammonia removal products will slow down bacterial growth.

    Also your tank is too small for Tetras. I suspect they will constantly overload the cycle. And depending on the food offered, leads to the oil slick. Other causes are lotions on your hands, too much of a bioload and too little surface disturbance.

    I recommend daily water changes until cycled and running an air line over night. This will eventually clear up that oil slick.

    Good luck.
     

  3. bowcrazy Well Known Member Member

    As catsma stated, your tank can’t be fully cycled if there is an ammonia reading of any kind. The size of the tank, the size of the filter media and the number and size of the fish is going to make it hard for you to keep a safe tank. One quick note – don’t change your filter media, just give it a good rinsing in your old tank water when you do a water change. You will loose to much of the good bacteria by changing it. Also using ammonia removal products can starve the good bacteria of what they need to grow. Products like Prime and Amquel+ will not remove ammonia but rather make it safe for 24 hours by detoxifying it.
     
  4. iRun Member Member

    What type of substrate are you using? I have a planted tank with Eco Complete and it has surface film, my planted tank with gravel has no film. After a lot of looking around, it seems that film is a pretty common problem in planted tanks. I gave a canister filter and use the fluval skimmer.
     

  5. fallemnier Initiate Member

    irun- im using flourite for substrate. i read that too.
    catsma- That makes sense with the food
    bowcrazy- the only filter media i replaced was the activated carbon. i just rinsed the mechanical and bio filters.

    thanks for the help guys. ill take out the ammonia remover and get myself and airpump and stone.
     
  6. bowcrazy Well Known Member Member

    By replacing the carbon filter media and rinsing all the rest you could of caused the tank to go into at least a mini cycle. Over cleaning the filter can even cause a complete crash of the cycle if the ammonia level is allowed to get to high. What are your current test results?