Like everyone said there's normally no need to add nitrifying bacteria to an established tank. It's kind of a waste, really. Nitrifying bacteria colonize whatever surfaces they can and filters are intended to provide prime real estate in the form of media and water flow, so in an already cycled system you'd essentially be adding superfluous bacteria with no place to go. I don't even do it with a new tank, I just take a bit of mature media from a running tank (or an extra filter) and stock lightly at first, but if you don't have that option some of the starter bacteria products are better than others.
Based on their product descriptions it sounds like the two Tetra products, Filter Active and Cleaning Bacteria, are blends of nitrifying (ammonia and nitrite eating) bacteria with sludge eating bacteria, with Cleaning Bacteria probably heavier on the sludge eating bacteria. I've seen other bottled "sludge removing" aquarium products. Rid-X is essentially the same thing, but putting "aquarium" on the label means you get less product for more money, like with poly fluff and "aquarium salt."
Regularly adding probiotic, sludge removing bacteria is optional, not a requirement. Probably the heavier you feed and heavier your tank is stocked, the greater the benefits for your filter cleaning schedule.