I have to disagree completely here. one of the main benefits of cannisters is, long periods between cleans. as back2Fsih says. true, if you have reduced flow, the filter needs cleaned. but if that happens, in two or three weeks, something is wrong. perhaps over feeding?
according to who? because im almost certin that no manufacturer is going to suggest you wait 6mo between cleaning your filter?
and as i clearly mentioned earlier. by the time there is a noticeable difference in flow, your filter has already been hindered for way too long. canister filters are only rated to handle a certain amount of head pressure. (something like 4-5', depending on the manufacturer). this is usually marked by the length of the hoses that accompany your filter. the more unnecesary strain put on the motor beyond that can cause your equipment to break down much sooner than intended. (and people wonder why their filter leak. bahahahah. )
as far as i can see, most of the waste taken in by your filter is broken down, completely. (if the filter is working efficiently) not kept in the filter. i last cleaned my Eheim, a month ago. it had been 13 months since the last clean. (flow has slowed, noticeably, but not excessively, in that time.)
as mentioned earlier. not all solids are broken down. and as mentioned earlier (noticing a trend here?) dissolved solids do lower your PH, and have other negative effects on your water parameters.
remember, you can clean your media as carefully as you like. but you will still loose valuable bacteria, when cleaning.
i think this sentence explains exactly why you so foolishly disagree. it seems like someone has tragically misinformed you on this matter. if proper precautions are taken (IE. using decholrinated tank water, not TAP water. not allowing your media to dry out or go for extended periods without food and air. etc) you run absolutely NO risk of loosing enough bacteria to make a difference in your cycle.
as i said, i clean my filters every week to two weeks. i guess that disproves your "theory"
@back2Fish. you are not the only one surprised by bitteraspects comments. his "common sense" approach, honestly makes no sense. an effective filter breaks down the waste. if its truly, effective. all that is left in your filter is fibrous matter. and that cant break down much further. i would postulate that the reason he needs to clean so often is, that he does not have enough bacteria to "effectively" clean for the fish he keeps. that's not to say his fish are kept in any "bad" way. they just require more effort, than necessary, to keep that way.
BAHAHAHAHHAHAH. you would "postulate" WRONG!
not once did i ever say i "need" to clean my filters that often. merely that i CHOSE to. when performing weekly WC/ gravel vac. etc, why would you NOT take an extra 5 minutes out of your day to give your filter pads a squeeze in a bucket of tank water? youre already in ther tank and doing cleaning. whats 5 more minutes?
i CHOSE to clean my filters regularly to benefit bot my equipment and my fish. i GUARANTEE, my equipment will last much longer than yours if only due to its cleaning schedule.
As bitteraspects says
you just need to decide for yourself how you're going to do it
. but, to me, there is no point in making work for yourself. especially when all the evidence points to the fact that over cleaning is as bad, possibly worse, than low maintenance.
and again i ask, what "evidence"?
ive been keeping a weekly to bi-weekly WC/cleaning schedule for many years, and have yet to have any negative outcome because of it. guess there is no "evidence".
as for "why make more work for yourself"?... how about because your fish and equipment rely solely on you for their maintenance, and were only talking about 5 minutes a week.
5 minutes is a cigarette break, or the time it takes to walk down the driveway to get your mail. 5 minutes is a single television commercial, or one song on the radio.
if an extra 5minutes a week is too much "work" for you, i feel sorry for the way you were raised.
my advice. clean when you notice a drop in flow. judge, when you open the cannister, just how dirty it is. if you are getting clogging in some areas for the media, consider a change of type. six months seems to be the average for cannisters, though there is not rule. you will eventually gain experience of your system. this will allow you to "tailor" your cleaning to your, particular, environment. but i ,too, can say my system works with no ill efects on my fish. (i have never lost a fish to illness. indeed dont loose fish). so, if both work, why do any extra work?
clearly i can not speak for EVERY manufacturer, but i have NEVER seen any canister suggest you only do cleaning/maintenance every 6mo. i have seen 6-8 weeks (eheim), but NEVER once have i seen a manufacturer s instructions include the words "do not clean for 6 months".