How much beneficial bacteria is there really on decorations, like fake plants, caves, etc? The reason being I'm in a situation where I'm forced to swap filters without being able to run the old n new simultaneously. I've posted a question on swapping filters and was told to run them both till the new one catches up. What I did do was pack some stuff in the old filter for like two weeks. Then I also moved all the deco to the new tank and took the old filter pads and some parts of the old filter and sat them in the new tank. How likely am I to have a huge spike?