Cycling - How Long Should it take

[andrem]

I have had my tank cycling for 7 weeks, Took about 2.5 weeks for the ammonia to peak and drop and have had high nitirte levels since about the 1st week. These are still high (off the scale on a salifert test kit) as is my Nitrate which I have just started testing.

Wondering how longs other tanks have taken and also if any point in doing a water change at this point to get the nitirte down or just to leave the tank and keep on waiting.

Other thing I have also considered is adding some cycled rock but have had differing opinions on wether this is going to help/hinder the process. Unfortunately I hadnt read about "cooking" rock before I setup the tank otherwise that would have been a better option....still learnt something for next time!

[wasp]

Mostly takes 6 weeks, but will sometimes take longer. Your ammonia cycle was a tad longer than normal, so perhaps the nitrite one will be longer also.

Nothing much you can do at this stage, just hang in there, it will happen!

[JDM]

I had a similar problem when I cycled my first tank, I did a 90% water change after waiting 10 weeks for nitrite to drop, this left a nitrite reading of about 5 (from memory) and that dropped over the next week.

Not sure if the experts would agree with this method though.

I just matched the temp and salinity and dumped it in.

This is provided you don’t have any animals in there at the moment.

[raeh1]

I dropped a crushed mussel into my one, got it down to three weeks.

Also was given a seeded rock to help

Each tanks different though

[andrem]

I was wondering if the water change would help. I did actually start with a muscle in there, but removed after a few days once the ammonia peaked...maybe not so wise but then forums I have been reading say the dead matter in the rock would be enough anway. I kind of figure changing the water cant hurt and because my nitrate is so high I must have nitrosomonas bacteria present to be converting the nitrite. My last tank (years ago) cycled in about a month but guess you get that.

There are also no fish in there.

[reef]

i would just leave it as sometimes it can take longer. do you have the lights on? found that haveing lights on whislt cycling speeds up the cycling period.

also add live bacteria like bio digest . hollywood used it and the tanks did cycle quicker.

[andrem]

I did have however have been doing a bit of research and apparently nitrosomonas do not multiply as quickly in lit conditions and do not like blue light. Turned them off. Will leave for another week i think and see what happens. Also have a lower sg should help but i think i read the presence of phosphate restricts there rate of multiplication also.

[Feelers]

I think there was some research recently that concluded that the bacteria involved in aquariums was primarily from the Nitrosococcus genus. The conclusion was that while out in the "real world" nitrosomonas were responsible for the N cycle, but that in aquarium systems there was a rather dramatic shift, there were virtually no nitrosomonas at all. Nitrosococcus is thought to be filling the gap.

http://aem.asm.org/cgi/reprint/67/12/5791.pdf

Nitrosomonas marina-like bacteria were 2% or less of the cells detected by fluorescence in situ analysis in aquaria in which nitrification was well established.

It doesnt help you out much with your problem sorry andrem, but it shows that we are are still very much in the dark about these matters. 8)

[andrem]

Thanks for all the help guys, nitirte dropped overnight yesterday, have done a big waterchange and nitrate now very low also, added my first fish (pair of clowns) tonight!. Nice to have something swimming in there!

[wasp]