Diatoms are caused mainly be light and ammonia. During cycling there is a lot of ammonia in the water, there's nothing which can be done about this as ammonia is needed to grow the bacteria. But tank lights can be turned off if there are no live plants - and the bacteria grow better in the dark. But once the tank is cycled, they usually disappear, though it is impossible to say how long this will take as every tank is different.
Dr Tim's One & Only is one of the best bacterial starters but it will not work if it's ever got too hot or too cold during shipping or in the fish store. Since it has to travel from the USA this is quite possible.
Cycling needs patience. It took a total of 7 weeks for my tank to cycle, and 21 days before any sign of nitrite appearing.