Q&A: How Do I Know If My Filter Is Adequate For My Fish Tank?

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So you just bought yourself a new external HOB fish tank filter for your 30L fish tank.

The filter specifications say it’s capacity is 250l/hr & you cycle the tank before you gradually start adding fish.

Well, it seems like you have done everything right, but how do you know for sure?

When you think about it you might worry;

  • Is the water getting oxygenated/cycled enough?
  • There’s not a lot of surface disturbance from the water that’s being pumped back through the filter, is this a bad thing?
  • Is the filter capacity enough for your tank.

Before you panic here’s a few thing to consider about your HOB filter.

The main role of a filter in most fish tanks is to provide a place bacteria to live and transform the waste products of fish into less harmful forms.

Fish waste and food create ammonia and the beneficial bacteria growing in your filter removes the ammonia by turning it into nitrite and ultimately nitrate.

This is called the nitrogen cycle.

Nitrate is only removed from your tank when you change the water, so don’t forget to do your water changes.

The flow rate of the filter does not determine how effective the filter is.

The effectiveness of the filter is largely based on how much surface area is present in the filter for the bacteria to grow & live.

The flow rate ensures the bacteria growing in your filter is continually exposed to the waste (Ammonia) found in your tank.

The best way to determine if a filter is adequate for your tank is to monitor your fish as well as the water chemistry.

If your fish are showing any of the following signs, it could be a sign of a water imbalance and not enough filtration;

  • Extra aggressive behaviour
  • Swimming near the surface
  • Swimming on their sides
  • Dying.

Be sure to test your water regularly to monitor your ammonia/nitrate/nitrite levels.

If you find high amounts of ammonia/nitrate/nitrite your tank may still be cycling or your filter has not yet developed the beneficial bacteria needed to handle the ammonia levels in your tank.

This is why you need to stock your tank gradually.

If high levels of ammonia/nitrate/nitrite are not alleviated after a modest (40%) water change, then either your filter is not big enough or you are not changing the water often enough.

Need help with aquarium maintenance check out the 30 Day Easy Maintenance Schedule.

By | 2017-03-04T14:30:34+00:00 April 26th, 2016|Aquarium Maintenance, Fish Tank Filters|Comments Off on Q&A: How Do I Know If My Filter Is Adequate For My Fish Tank?

About the Author:

Jack Dempsey has over 20 years of experience with freshwater aquariums, his goal is to help beginners avoid the biggest mistakes when getting started. If you find something helpful please share it on your favourite social network. If you need help with anything send Jack a question.