If you totally bleach and clean everything you'll have to start from square one with the cycling process. I would start with one fish to start the cycling takes 6-8 wks until an established tank.
Nitrogen Cycle by Byron
Toxic substances are produced at various stages whenever fish (and plants) are placed in an aquarium. In a biologically balanced aquarium, exactly as in nature, living organisms (bacteria) remove or convert the various toxic substances through what we term the nitrogen cycle. Ammonia is the first toxic substance and it is produced by all fish through respiration, excrement and urine, and it also is produced by all decaying matter (plant and fish, uneaten food, etc). Ammonia is highly toxic to fish and plants. Ammonia (NH3) is consumed by nitrosomonas bacteria by oxidation, creating nitrite (NO2), the second stage of the cycle. Nitrite is also toxic, although slightly less so than ammonia. Another bacteria, nitrobacter, consumes nitrite and converts it to much less toxic nitrate (NO3) which is released back into the water. Nitrate is only toxic at very high levels. In a biologically established aquarium nitrates are used by plants (if there are any) and algae as nutrients, some is converted by anaerobic bacteria in the substrate and the filter (sometimes) to obtain oxygen [nitrogen gas (N2, another toxin) is always produced in this process and it is released at the water surface], and most of it is removed through regular partial water changes performed by the aquarist.
It takes time for each of the bacterium to become established, and that is the reason for the 2-8 week cycling period. Nitrosomonas bacteria will only appear if ammonia (their "food") is present, and similarly nitrobacter bacteria only appear when nitrite is present. Both types of bacteria multiply (through osmosis) as their respective food sources increase, and if the ammonia or nitrite should decrease, the respective bacteria will die off accordingly. Once established (after 8+ weeks) they can multiply fairly rapidly to handle increases in the bioload provided the increase is not too great. That is why you add new fish slowly and over time, so that the bacteria have time to multiply in relation to the additional "food" which is important to prevent stress on the fish.
There is one further element to mention. At an acidic pH (below pH 7.0) ammonia largely converts to ammonium which is not toxic and is used by the plants. Nitrobacter will still use ammonium as well as ammonia so the nitrogen cycle is the same. Your ammonia test kit reads ammonia and ammonium equally as ammonia, which is fine for the purpose of knowing what is occurring with the nitrogen cycle. In an aquarium where there is ammonium in preference to ammonia, and if there are plants, the plants perform much of the function of a biological filter, which is one reason why living plants are a practical component of an aquarium.
Vancouver, BC Canada
Hope this helps it helped me