Your filter uses a blue media or sponge (or something like it). When you cycle a tank the idea is that you build up a colony of nitrifying bacteria in these filters. Fish pee (through their gills); they pee ‘Ammonia’ and this is HIGHLY toxic and damaging to a fish’s health (short term and long term effects). The nitrifying bacterial colony munches this ‘Ammonia’ into the slightly less toxic Nitrite. Another (slower growing) bunch of bacteria then munch up the Nitrite into the far less toxic Nitrate. The levels of Nitrate (and of course ‘Ammonia’ and Nitrite) are kept low by regular weekly water changes.
These Nitrifying bacteria are sessile (i.e. they are permanently attached to something and are not free to move about); they don't ‘live in the water’ per se, but rather live stuck to things like your filter media (which for this reason has a large surface area in the form of a sponge), rocks, walls of the tank, plants and so forth.
Hence, what are LACKING from a new tank are good bacteria (that eat Ammonia & Nitrite), be it in the substrate, on the glass or in the filters. There are no issues with bad bacteria per se because a new tank will be more or less sterile.
Nitrosomonas marina are the main Ammonia oxidizing bacteria & Nitrospira species seem to be the main Nitrite oxidizers.
To get the good bacteria going, add Mulm to the substrate & filters (if you can - the best kick-start and will greatly reduce the cycle time) and then get them growing by adding pure ammonia on a daily basis.
Regular testing from then on will tell you if your tank has cycled and you can add fish, a process that will take probably 5 to 6 weeks (minimum).
There are 2 ways of cycling a tank. With fish or without; both provide a source of food for the bacteria in the form of Ammonia (so that the colony can start to grow), be it from fish pee or adding it by hand. The ‘with fish’ cycling technique (unless you are experienced at it and know what you’re doing) is considered cruel because during the cycling process (which WILL take weeks) you are poisoning those fish because there will not be a large enough bacterial colony to deal with ALL of the ammonia produced by the fish.
Cycling a tank without fish couldn’t be easier. You simply add PURE ammonia (an amount determined by the size of your tank) day by day. Then you monitor the levels of Ammonia, Nitrite and Nitrate. Once your Ammonia & then your nitrate levels have gone up and then back down again and then nitrate levels go up, your tank may be considered initially cycled and you can start adding fish.
Fishless cycling. Two methods in one thread:
http
/www.fishforums.net/index.php?showtopic=113861
For cycling, use pure ammonia that does NOT foam when shaken i.e. produce soap suds as it will have detergents in it. Use household ammonia from boots or Ammoni sold by Kleen-Off. Also see here for sources of pure ammonia:
http/www.fishforums.net/index.php?showtopic=38840
Once finished cycling - do a large 50% water change and stock to 75% maximum.
GL
Andy
