I disagree meggie. Bacterial blooms, while its true that what you're seeing are actual bacteria, are the result of waterborn heterotrophic species of bacteria that eat organic materials (which are the thing in excess in the tank and the cause of the bloom) and create ammonia from it. These are completely different than the biofilm living autotrophic bacteria that we grow in our filters. The autotrophs do not form big visible blooms and filter bacterial growth is not the cause of blooms.
Its true that actual milkish looking bacterial bloom is not harmful to fish, but the ammonia that's likely to be produced can be quite harmful and its not desirable to be experiencing a bacterial bloom in a tank with fish in. Bacterial blooms during fishless cycling are common during the early stages and are normal and harmless to the fishless cycling process.
Using chemical pH adjusters, regardless of which direction they're designed to push your pH in is not a recommended practice in my experience with fishkeeping or here at TFF. The number one choice with respect to pH is to live with the pH of your tap water and plan your tank and stocking with it in mind. If the decision is made to alter the pH (and its a serious decision) then there are other ways to either raise, or, with more difficulty, to lower the mineral content and secondarily the pH as a result.
~~waterdrop~~
