By taking media from a established tank (one over 6 months old) and adding a handful of gravel/sand from the same tank the tank will effectivly be cycled instantly, as long as stock is added slowly so the bacteria that were transfered can cope then you will never see a ammonia or nitrite reading (remember that the fish must be added at the same time as the media so that the bacteria has food to live on, bacteria colonies die off rapidly without a food source).
Liquid bacteria products are worthless IMO, the bacteria have been placed into suspended animation and can only be woken by very spesific water conditions, establishe media and gravel are far better sources of instant bacteria.
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