I had an old tank which is 40L that i stopped using about 2 months ago. I have set this back up, dechlorinated the water and currently only has a sand substrateand no plants. It has been set up for a week and i have had no bacterial bloom. I originally use the old filter for about 4 days (the filter has been out of water for 2 months) but i have switched to a brand new sponge filter. I am confused as to why the bacteria bloom has not started? I have been using fish flakes and pellets as my source of ammonia. Thanks in advance