I would like to know what people think about the products you can buy now when starting a new tank. I'm thinking specifically about Tetra Safe Start. I only mention Tetras product because that is the only one i'm aware of. If other products are out there I would welcome peoples opinions be they good or bad.
If using these products, then Tetra Safestart and Dr Tim's One and Only products each use the same recipe and have the correct species of nitrite eater required; however, their effectiveness if very much dependent on ensuring that the products are kept under the correct conditions at all stages from manufacture to actual use which of course can't be guaranteed. Other products generally don't have the correct species of nitrite eater required although I have read positive reports of Microbe-Lift Nite-Out II - it's not clear what its recipe is, though.
I use Tetra Safestart, always successfully, in situations when I'm setting up a hospital tank and remove a portion of filter media from the main tank filter, then top this up with new filter media embedded with Tetra Safestart. It may be that this success (i.e. keeping ammonia and nitrite at 0, and not having nitrates rise more than 20) is simply because I have the hospital tank already cycled with the portion of cycled filter media, rather than the Tetra Safestart, but having the additional filter media wrapped around it embedded with Tetra Safestart provides me with peace of mind.