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Discussion Starter · #1 · (Edited)
I changed a 72 bowfront I have from freshwater to saltwater. I took some water from my existing 29 gallon reef tank, and well as some bio filtration media that had been supplementing my 29g reef tank filter, some live rock (not a whole lot... maybe around 5-10 pounds), and I think a little aragonite from my 29g, and put in the 72 (I think I added a little aragonite from my 29g later on in the cycling process, as well). I threw in some mysis shrimp to try and kick start the cycling process. Somewhere in the month I added about 50 lbs of dry rock ( Anyway, I think that was about a month ago. I tested the water a few days ago, and from what I remember ammonia and nitrite were down, but nitrates were present (roughly 5-10 ppm maybe).
Well... a friend of mine had taken down his 75 gallon reef tank that had a bunch of live rock in it, I obtained about 50 pounds of rock from him for a good price and added it to the tank a few days ago. I tested the water about a day ago, and ammonia and nitrites did not seem to be a big deal, but there were some nitrates (5-10 ppm).

Now for the question :)
Even if my tank had gone through the "month long" nitrogen cycle, which it seems to me that it was close enough, and if the LR was well seasoned, when can I expect to see a spike in the nitrogen levels, if I get one?
How many days of consistent water parameters should I wait before I can safely disregard the possibility of a nitrogen "spike"?

oh, and... the polyps in the photo were on the rock when I bought it


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nitrate for the most part needs to be removed via waterchanges or algae growth (though some breaks down in low oxygen zones in large rocks or DSB). To consider the nitrogen cycle complete you should read 0 ammonia and nitrite. The addition of cycled live rock should not start this over if it is kept wet and there is no die off on the rock. If there is some die off you should really only see a mini spike in ammonai and then nitrite.
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