I'm also in defence for the add and wait method. I've cycled and fully stocked my tanks using that method and have never ever seen any ammonia or nitrites in the tank since cycling finished.
I'm a scientist and I can tell you now that any system that builds up enough bacteria to manage massive amounts of ammonia in a few hours is definately better than any chemical in a bottle. The add and wait method takes advantage of bacterial growth by supplying a steady and abundant supply of food for those bacteria to promote duplication in the filter sponge. The only type of additive that you should add would be bacteria from an established tank.
If you want to speed up the growth of bacteria turn your temperature to 30 or 32 degrees...anything close to 37 if you can.
If you want to use the chemical in your tank from the pet store try it without fish in the tank and add ammonia artificially, that way you wont hurt your fish and you can really find out for yourself if the product works. I have used cycle as it was recommended to me from my pet store but both bottles I got were absolutely rubbish and a complete waste of my money.
You say that you have done 50% water changes and that you have managed to bring the nitrite down to 0.1, wouldn't this suggest to you that this is because you have simply removed the nitrite from the water by doing the water changes and have diluted the remaining nitrite with fresh water, by doing this you are removing the benificial nitrite that is in the water and will effectively slow down the rate of bacterial growth and you
will have problems with nitrite spikes later if you dont allow the bacteria to grow naturally in your tank. A nitrite spike usually only lasts for a few days and I have found in my own tanks that a nitrite spike goes down pretty quickly, sometimes over-night.
There is no point rushing this process, if you do you will lose fish and disease will occur more frequently as the fish will be stressed with the small amounts of ammonia or nitrite in the water.
I hope you take this advice on hand and try not to listen to your pet store all the time, they are there to make money while we are offering free advice from our own experiences.
