New Filter 29 Gallon Tank

Discussion in 'Filters and Filtration' started by Agrajag, Apr 12, 2010.

  1. Agrajag

    AgrajagNew MemberMember

    Hi everyone

    This is my first post. I am not really in need of help at the minute as things seem to be under control, but need to understand what may have gone wrong so that it doesn't happen again.

    On friday I bought a new external canister filter with UV which I plumbed in and set going. The original Internal filter was left in to allow the new filter to mature with the uv off.

    I used filter start in the canister filter to get that going. The new filter is rated for tanks up to 400L although my tank is 100L but I am gearing up to get a bigger tank and the lfs guy said the additional flow in the small tank would do no harm.

    I woke up on saturday morning to find my water extremely cloudy and all the fish (those that were still alive) gasping for air at the top of the tank.

    I tested my water and ammonia was undetectable but nitrite was off the scale.

    I changed around 40% of the water immediately followed by another 30% a couple of hours later. That brought the nitrite down to about 4ppm, and the fish were looking much happier.

    By sunday the nitrite was undetectable.

    The tank has been up and running only 6 weeks but no new fish have been added in the past two weeks.

    In short, why would adding a new filter cause a massive nitrite spike if the old filter was still up and running?

    Thanks In Advance

  2. Meenu

    MeenuFishlore VIPMember

    Welcome to FL, Agrajag.
    I can't think of any reason that adding filtration would cause a nitrite spike. In fact, I think that this is a coincidence in the timing. Do you know if your tank was already cycled?

    I am thinking that the nitrite spike was going to happen anyway because of the tank cycling. It seems about the right as far as timing... cycling can tank a couple of months, even longer in some tanks.

    At this point, daily water changes with a detoxifying conditioner like Prime will be the best thing for your fish.
  3. OP

    AgrajagNew MemberMember

    Thanks Meenu

    I thought tank had already cycled. This is our second tank (My GF has had one for 5 years) so we were able to use filter material,gravel and some water from her when we set this one up.

    Before I put any fish in I had an ammonia spike followed by a nitrite spike a couple of days later (I fed the tank with flakes). When I put in my first fish I did get another set of smaller much smaller spikes. After that all levels stayed at zero even when adding more fish so I assumed it had cycled properly. Other than watching for the spikes, how do you really know?

    As Nitrate and ammonia levels are now ok would you continue with the daily water changes or go back to weekly? I am a little baffled as this all happened very quickly but was also over very quickly too?

    My best guess was that I had maybe overdone it with the filter start and caused some kind of bacterial bloom or that maybe the increased flow rate had churned up something in the gravel.

    Any thoughts?
  4. Craig-D

    Craig-DValued MemberMember

    If all your levels were at zeros after adding your first fish as you stated, then the tank was not cycled. You would have had a reading of some nitrates in a cycled tank. The fact that you had no ammonia reading, but nitrites were "off the scale" is further proof that you were in the middle of a cycle. You should be showing 0 ammonia, 0 nitrites, and at least 5 ppm nitrates consistently before you are considered fully cycled. Only then can you go to a regular weekly water change schedule. For the first month after a new tank is set up, I check the water daily, then after a few days of consistent good readings, I taper off to weekly, and then eventually monthly. Whenever you alter anything in the tank, like adding new fish, vaccuming gravel, or changing media, test again a short while later. Always keep an eye on your water and always be aware of its condition - the smaller the tank, the more imperative this vigilance becomes.

    One other thing to keep in mind is about the UV sterilizer: make sure it is indeed off when you intend it to be off. It will kill any beneficial bacteria that is free-floating in the water. Though beneficial bacteria is usually attached to something and not free-floating, some of it does become free-floating whenever you disturb the substrate or the filter media. Be mindful of that when you vacuum your gravel for example. If that UV kills enough of your bacteria, it could cause a mini-cycle.
  5. Meenu

    MeenuFishlore VIPMember

    I always have thoughts... I talk (and type) way more than anyone wants to listen to. :)

    Do you have live plants? It's the only explanation for 0 nitrates in a tank that is cycled (that I know of).

    Even if your tank was previously cycled, it is clear that it is in a mini-cycle now. I still wouldn't think it has anything to do with the new filter, though...
  6. OP

    AgrajagNew MemberMember

    Hi guys, Thanks for all your help

    You are all correct the tank is cycling now. Ammonia got up to 0.5ppm and is now falling, Nitrite was just about detectable last night and I will check again when I get home. I am hoping Nitrite levels aren't going to get too high as fish are in there now.

    Apologies for confusing some of you when I said I had zero Nitrate I meant Nitrite. LFS guy said a lot of people are having problems at the minute as local water has tonnes of chlorine in it right now.

    This Filter is the start of my new set up, I can't afford all this stuff at once so it is probably going to look some thing like this.

    April: New Filter
    May: New Cabinet / Stand + Inline Heater
    Jun: New tank
    Aug: 2nd Filter

    The tank I am thinking about is this one.
    Length: 72 inch
    Width: 18 inch
    Height: 24 inch
    Glass 10 mm
    Volume 468 ltrs

    Although I may go for a shorter wider one.

    If anyone has any thoughts/advice on this set up then please let me know. If you like I can keep you up to date with photo's etc during the build.

    Thanks Again