Fishless Cycling - Nitrates Gone Wild! Help plz

[grenathor]

My 30 gal tank has been cycling for 3 weeks now. I kick started my cycle using filter media from another well established tank. I kept an ammonia level of about 2 PPM in the tank for the first week. After the first week, the tank could cycle 2ppm ammonia in 24h, and nitrites started to show considerable concentration between 0.5 and 1ppm. For the second and third weeks, I kept 1ppm ammonia in my tank daily which was easily cycled in 12 hours, nitrites have "stabilized" at 0.5 - 1ppm, and nitrates started to show at the beginning of the third week (5-10ppm). During the third week, I kept on adding ammonia daily to keep 1ppm, nitrites still show 0.5 - 1ppm but Nitrates spiked horribly high (way above my test kit limits). I was taking daily ammonia/nitrite readings, but I was checking for nitrates only 1/3 days. Yesterday I made a 90% water change (Brought water down to about 1/2 inch above substrate). After the WC, readings were: ammonia 0, nitrites 0.1 (slight coloration), nitrates 20ppm. Tested tap water which read 0/0/0.

Now what I don't understand is why is there always nitrite in the water even though the bacteria seems to be established because my nitrite won't go up as I add ammonia, but it won't go down either even if I read huge nitrate spikes. Should I keep adding daily 1ppm ammonia to keep the cycle up and give it another week? Or should I lower the ammonia to 1ppm every other day to give nitrite a chance to get down?

Something I forgot to mention: there's an amazon swordplant in my tank and an apple snail

Thanks

[bderick67]

With seeing a large amount of nitrates such as you have I would say your benefical bacteria(BB) colony is now strong enough that you could start adding fish to that tank. Don't know what your projcted stocking is of this tank, but I would add 3-4 two inch fish and monitor for a couple weaks. Basically you are looking for the balance between the bioload and the BB, so add fish slowely so the BB will have time to adjust to the increased bioload.

[Cory Keeper]

In my experiance nitrites are processed much sooner than ammonia is. As long as you keep adding ammonia you will still see some nitrite, it will just hold. But since you had over 160 PPM (im assuming here) of nitrates, it sounds like you are cycled.

[southpaw]

I would give it another week and continue to dose with ammonia to be on the safe side....you have waited this long so another week should be a walk in the park :)

I think it is better to be sure ...as you said you are still getting trace amounts of nitrites so another week should get everything right were it needs to be hopefully

[jm1212]

make sure to monitor everything though. if something esle should swing, say ammoina or nitrites, levels that are to high could effect the cycle

[grenathor]

thanks for the info

I lowered the daily amount of ammonia to about 0.5PPM and nitrites started to lower slowly, so I guess i have somewhat of a cycle going on in there, just not yet ready for a heavy load, but it should be enough for now. Today I was reading 0 ammonia, 0.25 nitrites and off-scale nitrates once again! So I did another 90% water change, now everything is at 0 and pH is 7

[grenathor]

I think it has fully cycled, after last night's WC I put 0.5ppm ammonia in my tank, this morning, 0 ammonia, 0 nitrites and about 5ppm nitrates in less than 12 hours

[Daniel_MoY]

Fishies!!