I took my aquarium apart. I was probably .ever getting the smell out. The sand smelled so bad itwas disgusting. I cleaned out the tank with some water and vinegar. I now have the Flourite in for the substrate with seeds down. To grow moss and tall grass. I am going to set it up the right way. I do believe the sand I was using was part of the problem. It just packed down not fluffy. I have the same sand in my five gallon tank. Having issues in that tank as well. Cycling a aquarium takes 4 to 8 weeks? Nothing can go in them at this time right?