Is it possible to overdose beneficial bacteria?

[aanubias]

Yesterday I asked on the forum about getting my ammonia levels down and someone asked if I had been putting beneficial bacteria in my tank everyday which I hadn't - I just followed what it said on the label. I was wondering if it is safe enough to add this bacteria in a bottle daily or is will there be any side effects? This is the liquid I use: https://www.fishkeeper.co.uk/aquacare-bio-boost-120ml

 

[Colin_T]

You can't overdose with beneficial bacteria unless you put the fish in a bottle of it.

I normally recommend adding a double dose every day for a week, then pouring the rest into the tank. Try to add the bacteria near the filter intake so it gets drawn into the filter where it belongs.

 

[Byron]

It may not cause problems for fish, but I see no benefit to be adding bacterial supplements once the tank is established. The nitrifying bacteria species responsible for using ammonia and the species responsible for using nitrite will colonize the surfaces and reproduce up to the level needed to handle the ammonia and nitrite respectively. They will not increase beyond this, unless ammonia/nitrite increases. So once established, there is no reason to be adding more. It can cause a bacterial bloom in some cases.