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What Causes My High Nitrate? Help

Discussion in 'Aquarium Water' started by Marijn Lange, May 19, 2019.

  1. Marijn Lange Valued Member Member

    I have a Juwel Bioflow 8.0 internal filter that has been running for six months. The tank is fully cycled. Throughout the months I noticed that my nitrite is always zero but my nitrate is always between 25 and 50. I have a decent amount of plants and I change 50% of the water every single week. I do not add CO2 or oxygen. The outlet is pointed towards the surface.

    Can anyone tell me what is causing my nitrate to be this high and how do I get it down?

    Maybe something that is important but I'm not sure. My plants haven't been doing great for the past two or three months. The leaves are turning brown and see-through and eventually they disappear.
    The perimeters are:
    NO3 | 25 - 50
    NO2 | 0
    GH | >7 - <14
    KH | 3
    PH | 7.2
    CI2 | 0

    Temperature 79F

    The stocking is:
    Five siamese algae eaters, one chinese algae eater, one bristle nose pleco, seven leopard danio's, four german blue rams and three electric blue rams.

  2. Jellibeen Well Known Member Member

  3. Rivieraneo Moderator Moderator Member

    It could be the plant decay itself causing the increased nitrates
  4. Marijn Lange Valued Member Member

    I have not tested my tap water. Good one! And yes, I do add fertilizer. V30 Complete basic fertilizer.

    Could be. But how do I keep them from desolving.
  5. RSababady Well Known Member Member

    I am assuming that this is a typo and it should read CO2. If it is CO2, then this is strange, as it would indicate that the reading was taken towards the end of the day as photosynthesis would have used up all the CO2 in the tank and turned it into oxygen. Doesn't feel right though.

    My guess is that there is inadequate gas exchanges in your tank, as you don't seem to have anything in the tank that is causing agitation of the water surface (that is where gases are exchanged), unless you have fans blowing air across the surface of the water, which dramatically increases the rate of gas exchange.

    As far as rotting plants go, yes they will raise your ammonia ==> thus nitrate levels are high (unless you have nitrates in your tap water which seems very common for the London, but I have never noticed any complaints from Rotterdam.
    Just cut rotting leaves off. They just use up minerals and energy unnecessarily.

    One thing to remember is that plants will use up nitrates in the tank water ONLY when there is NEW plant growth. Existing leaves use little or no nitrates. It is at the growth stage that plants consume nitrates.
  6. Marijn Lange Valued Member Member

    Ah, my bad! I meant to write CL2 instead of CI2. I’am referring to chlorine. I pointed the outlet of my pump at the surface to get surface agitation. I have used a power filter to get oxygen in to the water but there was no improvement in the plants.