So, one of the major tasks of aquarium maintenance is cleaning the filter. I prefer canister filters to HOBs (hang-on-back) although I do have one tank, a 20 gallon long, that has a HOB filter mounted on one end, rather than the back. That tank is so low to the floor that a canister wouldn’t work. (If you have a HOB filter, find a section of foam that fits over the intake as a prefilter, remove all the racks for mechanical media from the body of the filter, and fill the cavity with a bio media like Seachem Matrix. When the filter motor starts making noise, most likely because of cavitation, shut it off and squeeze out the prefilter, replace it and turn the unit back on. Easiest maintenance ever.)
First, how to tell if your filter needs cleaning? I find a schedule works best for me – there are several things I simply mentally “set” for “do the first weekend of the month.” However, I try to do my water changes once a week, and while I do them, I leave the canisters running. The intakes are all lower than the outputs, and I use a jet attachment and one of the aftermarket adjustable fan outlets, so it’s easy to tell once the water level drops whether or not the filter’s pumping out a decent amount of water. Recently I noticed that the flow rate in the planted tank was quite low, and when I cleaned the filter, the motor housing was a bit warm! Not the best situation. The problem: clogged polishing pad. I’ve actually removed the polishing pad and replaced it with some bonded filter pad material I had already cleaned and in storage; the polishing pad got washed out and treated with H2O2, and will go back on at a later date if I notice a lot of unsightly particulate matter floating about the tank. Some people toss polishing pads after use, but I find that they can be reused for some time if they’re rinsed out and treated with an oxidizer – bleach would do as well. Once the pad dries completely there’s no worry about any residue from either bleach or hydrogen peroxide.
In the base of my canisters, both Rena Filstar XP3 units, I have the 20ppi and 30ppi black sponges. These all get thoroughly squeezed out in dechlorinated water. The other baskets I fill with some kind of biomedia; on the planted tank filter, one tray is filled with eight nylon pot scrubbers, which occasionally need to be squeezed out as well. The next tray has a bit of crushed lava rock – the kind used as a mulch, hammered into smaller bits – and the bonded filter pads, to make sure no rock gets sucked into the filter. This unit isn’t filled to capacity; I don’t consider that a problem. In fact, most canister filters’ flow rates are calculated with no media at all, so stuffing the baskets full will cut down on the flow rate unless you have a fancy, expensive model that can compensate. The cichlid tank filter has a half-tray full of Seachem Matrix, and a pair of filter bags full of crushed seashell and aragonite, respectively. The top tray has more bonded filter pads, cut to fit the XP baskets; they’re actually also cut to hold a little bag of Seachem Purigen, which got taken out last filter-cleaning to be regenerated and hasn’t gone back in yet. On this tank, the lack of a polishing pad is evident – there’s always some particles floating about – but this is a feature, given that small particles are what cichlid fry depend upon as a food source!
In order to clean the media, I’ve discovered it’s easiest for me to simply set up a “cleaning station” right next to the filter, rather than lifting the heavy water-filled unit elsewhere. (Saves having to clear my kitchen counters of fish gunk!) I use two 2-gallon buckets, one to hold the cleaned media and support the motor housing on top, and one to hold about a gallon of treated (or tank) water at a time, in which I squeeze out the sponges. I end up having to pour out dirty water three or four times in the process – hopefully the garden appreciates it!
I don’t normally clean the intake and output hoses; if I’ve already got the assemblies pulled off the tank I’ll run a hose brush through, but I don’t go out of my way to clean these as they haven’t ever needed it so far.