All you need to add to a tank is just one water conditioner and if the tank has live plants maybe plant fertiliser. If you use an anti algae chemical, that is detrimental to fish.
Seachem Prime is useful when tap water has chloramine as a disinfectant. It splits chloramine into chlorine and ammonia, removes the chlorine and detoxifies the ammonia part so it doesn't harm the fish until the filter bacteria have had time to 'eat' it.
Where tap water has chlorine, the best water conditioner is API Tap Water Conditioner. This contains just 2 chemicals - one to remove chlorine and one to bind metals.
The fewer chemicals we add to a tank, the better.