i added my 12 baby rb's 5 days after i set up my tank, but had added a couple bottles of the cheap sh*t (cycle), and some gravel from a notha cycled tank, have not lost any to water conditions,i had really high amonia levels, i used amonia lock to change my ''bad'' amonia to ''good'' amonia, isnt that the way it goes, iv had to be on costent watch and watching the fish, went through a short period of my fish all being at the top of the water, with there heads sticking out, breathing hard, not eneough oxgen, in my water, the sponge i had put on my filter pipe to keep babies from being sucked up, was gloging my filter so my bio wheel wasnt turning and it was only running on half strenth, as soon as i added a pump and air stone ,cleaned filter sponge(with tank water, so not to kill good bacteria).. been doing my reading.lol,after i fixed theses problems, things have chnged alot, no more cloudy tank, water smells good, and amonia, is way down, so its easer to just waite and cycle your tank before u add your P's, just my 2 cents man..