Aquarium help > New tank syndrome & NH3 > what is a filter crash and why does it happen?
    Table of contents

    What is a filter crash?

    A filter crash occurs when the beneficial bacteria that are used biological filtration are killed, diminished or are removed.

    Crashing can also happen when no biological filtration is present and only chemical filtration is being used; eventually chemical media becomes exhausted.  

    How to spot a filter crash.

    One of the first signs of a filter crash is a sudden rise in NH3 and NH4, these chemicals are present in the waste from fish and with nothing to remove them they can quickly build up.  A seneye device will spot a sudden raise in NH3 and alert you.  Also a sudden change in temperature of PH may result in a filter crash so these two should also ideally be monitored. Understanding your KH will help prevent crashes.

    Stopping a filter crash is important and there are a few things that should be watched.

    1.       Never replace an entire filter sponge unless you have separate biological filtration such as ceramic media.

    2.       Try not to change too much water in one go as this can upset the natural balance. For regular water changes 30% should be the maximum.

    3.       Watch the use of chemicals near aquariums and ponds. Often beneficial bacteria are more delicate than fish so a small vapour of fly spray may not kill the fish in the tank it will most likely wipe out the bacteria.

    4.       Sudden changes in water chemistry can upset the natural balance so be especially careful if you are using aquarium chemicals to change water parameters.

    5.       Many medications are not bacteria friendly. Most fish illness is caused by poor water conditions, although medicating the fish is required; it will only address the symptoms of a poor environment.

    Once a crash happened the damage to fish and other life will occur soon after. 

    To learn more about the best way to recover from a filter crash click here.

    Why not invest in a seneye monitor and protect your fish?