The easy and effective way of cleaning Poret filter foam.
The performance of your filter is based on the water passing through it. If the filter becomes to blocked the flow rate through the filter will drop and effect the stability of the system. Ammonia levels will spike and cause damage to your fishes gills. Canister filters and Hang On Back filter (HOB) will need to be cleaned regularly due to the relatively small surface area of the foam pieces.
Even Hamburg Mattens Filters will show signs like the diagram below. There will be a variation between the water on either side of the HMF. On our heavily stocked African cichlid tanks this can be around the 6 month mark. For most community tanks this can be years. When this variation becomes more than 50mm or 2 " its time for a clean.
Cleaning a foam sheet is very simple and easy. It is best never to squeeze or crush the foam, as this will damage the inner cell structure of the foam. If the foam sheet is your biological filter always rinse the foam sheet in a bucket of your tank water. The chlorine and low temperate of your tap water will kill off the beneficial bacteria.
Removing the foam sheet can be tricky and it`s best to do it gently to prevent all the mulm dropping into your tank. This is not a train smash as once the filter starts up again the mulm will be drawn back into the HMF.
The pictures above shows the cleaning of the mechanical filter section of a HMF2.0. We are not worried about a die off the bacteria and so can use tap water to rinse it off. We clean the sheet by holding it firmly and repeatedly smacking the dirty side of the foam sheet against a flat surface like this concrete wall.
Its a horrible metaphor but the dirt acts like a passenger in a head on car crash, who has not worn a safety belt. The dirt shoots straight out the front windscreen and splats against the wall. Repeat this process until less mulm comes out. If it is a biological foam sheet dip it into the bucket of tank water and repeat the smacking process until you are happy with the cleanliness. Always remember to wash off the wall.
On some of our larger setups we use a process of in-tank cleaning, using 20mm piping and a Coke bottle with the bottom cut off. Start the syphon process making sure that you don't swallow any water*. Place the open bell end of the bottle against the foam sheet and give a gentle squeeze this will force water into the foam sheet. The combination of the syphon and the bottle returning to its normal shape will draw dirt and debris away. Start at the top moving side to side and work your way down.
* A dram of Scotch whiskey is the cure for any ingested fishtank water.
If you have cleaned the biological filter section of your HMF. Its a good idea to keep feeding to minimum for a few days after the cleaning. Keep an eye out for any fish showing signs of heavy breathing. This could indicate that their is an Ammonia spike and its a good idea to test for Ammonia.
We always dose our tanks with Seachem Stability after a filter cleaning. This ensures that the biological stability is maintained.