Oooh the smell

[Gizmo]

I got a problem with this tank. I just got my MH's up and running, and thus, took the glass covers off of the top of my tank. Since doing so, I can not explain the stench in my basement. (kinda like stinky basement guy) It there that much evap that would cause rot in the house? I've lost about 2-4Gallons over the period of 2 days. Does anyone else run into this problem? I'm at the end of my rope here, and I dont want to get rid of my tank, but this has to stop. Please help.

G