The Puffer Forum

You can get some gravel from the LFS. That also has bacteria on it. I started my cycle with a rock from an established tank.

bigfatfish wrote:Even without a source of bacteria?

Yes. What you need to provide, is something for the bacteria to feed on, either adding ammonia or adding fish food (which will turn into ammonia after a while). When there's ammonia in the water, the number of ammonia eating bacteria will start growing in the filter (and some in the substrate as well). Those bacteria will turn ammonia into nitrite, so after a while there will be nitrite in the water (the amount of nitrie is at the highest at about 3 weeks into the cycle). When there is nitrite in the water, bacteria that eats nitrite starts growning in the filter (and substrate). They turn nitrite into nitrate. So at about 3 weeks, you will find the nitrites going down, and you will find nitrate in the water.

As a comment to using substrate to speed up the prosess: It's the same as with using stuff from the filter: If you have a tank with a different SG than the tank you get your bacteria from, it's useless, as the bacteria don't survive the change of SG. It is possible to use an already cycled FW tank, and only slowly raising the SG (1.002 every other week, if I remember it right). In that way the FW bacteria slowly get the chance to adapt to the new situation.

Thanks Troender, I just need to be patient then. I would rather do it this way than risk getting some filter media from a source that may be contaminated.

Or, start out at freshwater in a tank cycled with SafeStart, then bump it up each week slowly until you get to where you want the water to be. The bacteria will adapt if you go slow enough. I know some people doubt whether SafeStart or Bio-Spira work, and I don't blame them but I bet they'd believe differently if they'd actually tried cycling a tank this way.

I can pretty much bet that whatever BW fish you are going to buy from a LFS, will be sold to you from their FW tanks. If they do claim their tank is BW, bring your own hydrometer/refractometer & test it for yourself, then cycle your tank at that SG.