Do the Nitrobacter and Nitrosomonas bacteria in gravel die when the gravel dries up? Or do they go dormant? *This is Asked in the context of an undergravel filter being used with about 4" of gravel and a powerhead.
I recently moved from Buffalo to Seattle. In doing so, I sold most of my fish back to the LFS, and put the tanks on the moving truck. But I brought my plants and a few favorite fish with me in some buckets in the car and trailer.
During the month it took me to find an apartment, the fish I brought with me lived in the pail with the plants in my rented room, and my tanks sat in storage in the moving truck at the ABF Freight terminal. During that time, the gravel completely dried out from baking in the truck in the summer sun. When I finally got my tanks out of the truck and moved into the house, the gravel was completely dry, and they smelled horrible.
I removed the gravel, rinsed it out well with plain room-temperature water, and scrubbed the tanks with a washcloth and sea salt. I set them up in the usual fashion, plugged in some plants, and set my 5-gallons of incarcerated travel companions free for their first good swim in six weeks.
I was expecting the usual 4-6 week cycle time for a new tank, but I was surprised to find that it snapped into shape in about a week. The usual phases of bubbles, cloudiness, greenishness, and floating bits all went by really fast. The last phase was about two days of milky clouded water, which flared up and later ended literally overnight, and then the fish were all perky and happy after that. Now I have the kind of sparkling healthy tank I am used to.
So in a situation like this, do the bacteria die or go dormant?