New tank

[CoralReeferGal]

So we upgraded our tank to the 120 and got it filled and LR in there. Waiting (impatiently) on the cycle so we can get our corals moved. Please forgive the stupid question, but do we just let it alone or should we do doing water changes during cycling? Everything tests good so far except ammonia. Were between 25ppm and 50ppm. He can't remember about the water change during cycling since it's been over 10 years since he cycled a tank lol and this is my first new set up. TIA!

[r-balljunkie]

did you start the tank with the old water, liverock and sand, or new?

makes a difference in the amount of time.....

[mpderksen]

Water changes during a cycle defeats the purpose. With ammonia, the bacteria population that breaks it down grows. Those bacteria produce Nitrite as a by product. As the Nitrite levels rise, another population that feeds on IT grows, and converts the Nitrite to Nitrate. (Correct me if I'm wrong in my understanding).
If I'm right, the ammonia level should start at about 2ppm. Once you can add some ammonia, in the form of a raw shrimp or raw ammonia (use the stuff without any perfumes or surfactants, which is a soap) the all levels hit zero the next day, you're done.
Ghost feeding, where you daily add a little food, but no fish, will keep the bacteria growing to the point they can handle the ammonia produced by the CUC when you add it.
One big reason to add fish one, or a few, at a time, is that the bacterial population will grow based on its food supply. Too much at once, and you get a mini-cycle. In that case, the total population has to expand, but does so in the same series as a initial cycle.
Imagine you have the supply chain for a restaurant. The owner orders just enough produce to match the amount of diners, so the shipping company stocks enough to supply all their restaurants. If you suddenly do a marketing blitz, first you run out of food, so you order more. But the supplier only has so much to deliver. He gets used to the load slower, because He has suppliers. Does that make ANY sense? (Too much watching Restaurant Impossible...)

I'm unclear myself where Phosphate fits into all this, since its traditional NOT to skim during a cycle.

[CoralReeferGal]

It was all new everything. We did get cultured rock but it was not from the old tank- all the rock we had has corals on it. We didn't test the water initially, our first test was approx 2 weeks after set up. Ph was at 8.4, nitrates and nitrites at 0 and ammonia between .25 and .50 ppm. Ammonia doesn't seem to be changing, tested the same last night (4 weeks post set up)

[mpderksen]

It was all new everything. We did get cultured rock but it was not from the old tank- all the rock we had has corals on it. We didn't test the water initially, our first test was approx 2 weeks after set up. Ph was at 8.4, nitrates and nitrites at 0 and ammonia between .25 and .50 ppm. Ammonia doesn't seem to be changing, tested the same last night (4 weeks post set up)

Bump the ammonia to 2.0 and check it daily for a bit. If it drops quick, that's good. It mean the bacteria load can handle what will be produced by the CUC. In the tanks I've started, it seems to hover for a while, then, like over night, it's gone. Sometimes I miss the nitrite spike unless I test daily. When I can drop from 2.0 to zero on all tests, I call it cycled.