Originally Posted by JamesMJ2
Not having to change the water is nice though
whoever told you that you do not need to change water is largely mistaken.
Unless you have a special setup on your tank (ie: very large tank with lots of plants and almost no fish), you will need to do regular water changes, weekly or biweekly.
Although a good filter will keep your ammonia and nitrite levels at or around 0, most do little for nitrates, which will easily build up to toxic levels without regular water changes.
there are "gizmos" that remove nitrates, and there is the so-called nitrafaction filter that uses anaerobic bacterica, but these are dangerous in their own accord and should be avoided by all but the advanced hobbiest.
using a filter to clean your gravel is dangerous as well ... with waste products sitting in the gravel, they are exposed to very little water flow, and therefore, release very little toxins into the water. however, if you vacuum all that 'debris' into your filter, it is now having a large amount of water circulated past it constantly... which greatly increases the amount of DOC
(disolved organic compounds) in your water.
I don't vacuum my gravel regularly, but I do have a large amount of plants and several bottom feeders. I also do weekly 25% water changes and maintain my canister filter once a month, with a more thorough cleaning every 2 or 3 months.
for montly maintaence I open the canister, replace the filter floss and clean the impeller cover, I also clean the intake strainer.
for the 3 month service I remove the canister taking it to my sink, wash the prefilter, rinse and temporarly store the bio media in tank water, rinse the canister itself with HOT water, replace the filter floss, remove the impeller and clean it and the motor, clean the venturi and primer plunger. I also take a bottle brush to my spray-bar, to clean out the holes and the inside. I then refill the canister with dechlorinated water to make it easier to prime.
about every 9 months, I remove the hoses and clean them with a bottle brush tied to a long wire - a lot of gunk builds up inside them, really reducing the flow. at this time i also clean the valves on the canister filter, which tend to gunk up as well, i also preform the 3 month service as well.
I use a fluval 404 on my 29 gallon tank. Before it was heavily planted, I ran the filter with the valve 1/2 open, but now I run it full open and the fish enjoy the current.
for my 4 media trays, I have the first two loaded with small pieces of lava rock, then a tray of the biomax rings, and then a tray of tightly packed filter floss. You'll notice I don't have any carbon or other chemicals in my filter. I rely on plants for the majority of chemical and biological filtration, and the canister is only used to provide some biological and mainly mechanical filtration. On occasion I will swap filter floss for carbon if I'm medicating or stirred up the gravel - it really clears the water quickly!
Sorry for the long post - I hope some of this information and advice is usefull to you!