Is my tank cycled?

[brandonmoss]

I have been doing a fishless cycle using ammonia chloride (first time doing fishless), i added ammonia to raise to 4ppm roughly 6 weeks ago. After roughly 4 weeks i saw a nitrite spike and ammonia was at 0.25ppm and nitrite was over 5ppm. Ammonia has now been at 0.25 for the last week and nitrites remaining at 5ppm. I added more ammonia to bring up to 1ppm twice and was both processed back to 0.25ppm within 12 hours but never to 0. I have now tested for nitrates and they are at 160 but nitrites still at 5.

My question is, has my tank cycled? And why is my ammonia and nitrites not dropping to 0?

Thanks

[Fish Tank Travis]

I would say no.

If you have 5ppm nitrite, then you do not have the beneficial bacteria that converts nitrite into nitrate. That level of nitrite will definitely kill the fish. It is odd that you have a nitrate reading without the proper beneficial bacteria.

As for the .25ppm, my test kit has never actually read "0" unless I am testing my tap water. It always reads .25ppm, even though it's been cycled and running for well over a year. It does sound like the beneficial bacteria that converts ammonia into nitrite is colonized.

You will want to keep dosing ammonia though. This is how you build up a good colony of bacteria. If you don't then the beneficial bacteria that convert ammonia into nitrite will start dying off after a while. You will probably see a crazy nitrite spike and then a crazy nitrate spike. It is not unusual to see nitrate levels off the charts at the end of the cycle. This can be handled by doing a few large water changes, which will get rid of the nitrates, but will leave your beneficial bacteria intact (as long as you properly condition your water).

They general rule I've heard is that you want to keep dosing your ammonia up to 4ppm every day, or at least every other day, until you end up with zero ammonia and zero nitrite after a 24 hour period, from the initial 4ppm ammonia. Then, do your water changes until the nitrates are down under 10-20ppm, and then add fish. For discus, you might want to try to get the nitrates under 5ppm, or as close to zero, as possible.

[DJW]

Your nitrite is off the chart, it could be 10 ppm and the color is the same as 5. Excessive nitrite can impede the cycle, so do a 100% water change to reset the whole thing to zero, dose 2 ppm ammonia and then see what it does over 24 hours. It looks like you have a complete cycle, its just that you have a backlog of nitrite.