Filter Media Bacteria

[Flumpus]

I've got a 75g tank with 3 mono sebaes, a green spotted puffer (who's permanent residence will not be in the tank sadly) and a couple mollies. It started out completely freshwater, and I've been slowly (very slowly) raising the SG with each water change. Over the past month or so, probably longer, I've brought it up to 1.005. My question is, now that some brackish bacteria exists in the filter, can I start raising the SG a little faster, or am I still at risk of causing a mini cycle if I go too fast? Thanks.

 

[nmonks]

I'd say carry on what you're doing, with nitrite checks each week just to be on the safe side. Going up a notch on the SG scale (e.g., 1.006 -> 1.007) each week shouldn't cause any rapid die-off of filter bacteria. From fresh to 1.005 seems to be completely safe and the bacteria remain the freshwater ones as far as we can tell. What happens above SG 1.005 is where the voodoo sets in, and I haven't seen anything convincing that tells me where the freshwater bacteria die off, or even if they do.

Cheers,

Neale