There’s a tonne of information out there on tank maintenance and fish keeping but very little that specifically addresses the correct way to clean your filter out WITHOUT killing all the friendly bacteria in it and so prompting a mini-cycle.

I’ve had friends and people on this blog contact me several times over the past couple of years complaining that all their fish have suddenly died for no reason.  I need to make something clear right now healthy fish do NOT suddenly all die for no reason,  the problem seems to be that people don’t associate their actions with the reason for the fish death.

The best line came from one of my friends “Well I look after my tank and clean the filter weekly so there’s no reason for the fish to die”.  After further digging it turned out he didn’t like the fact the sponges had changed from white to a mucky brown colour so he decided to bleach them and rinse them under the cold tap.  He’s not alone in this my mother of all people insists on putting new filter sponges in her filter every time she cleans it out!  I’ve actually given up on trying to teach her the proper method of filter cleaning.  Hopefully this simple bit of advice will help you all avoid the issues others have faced.

There is one main simple rule to follow and doing this one thing alone will save your fishes life.

Only ever clean your filter in tank water!

I follow this simple process.

• Half fill a bucket with tank water.
• Take filter out of tank if internal / If external isolate the hoses and disconnect it from the tank (leaving the hoses full of water this saves you having to reprime your system)
• Take bucket + filter over to sink (it helps to put the internal filter in the bucket save you dripping on the floor)
• Take filter apart in sink pour filter water away and put sponges/filter media in your half full bucket.
• Clean filter housing / plastic under normal tap water clean out the impeller and remove any crap build up.
• Solid filter media alphagrog /K2 / ceramic rings give a quick mix about in the half bucket then put back in filter DO NOT clean it under tap water.
• Give your sponges a good squeeze and rub together in your half bucket of water.  Now at this stage the water will be filthy and your sponges may not be clean yet.  Pour that half bucket away and get another fresh half bucket of tank water from your tank!
• Repeat above process again for sponges.  By now they should be clean.
• Put filters back together.
• Take back to your tank, connect up and turn on.

Your filter is now clean and working again, you’ve not killed any of the friendly bacteria off of it and you won’t experience a mini-cycle.  If your sponges are knackered and do need replacing do NOT replace them all at once.  Clean the filter as above change half of the sponges this clean and next clean change the other half.  This will ensure your new sponges are populated with bacteria asap and again avoid a mini-cycle.

At this time you’ve also conveniently removed a bucket or perhaps more of your tank water so you can top up using fresh water and now you have done your weekly water change all at the same time.

It really is as simple as that to keep your filter healthy.