Smelly odor coming from fishtank

[sweetjuicy]

Hi all, new comer here. My tank has a smelly odor coming from it, maybe sulfur like, but not for sure. It also kind of smells like the silicone that I used to replace the glass on the hood fixture. What can it be? Does anyone have any ideas?

Amm=0 Nitrate=20ppm Nitrite=0

The tank is 29 gal. w/ an over hang filter, airstone and I have used filtered water.

Please help me w/ my stinky dilemma!

Thanks in advance.

 

[gadazobe]

A sulphur like smell could be anaerobic spots in the substrate. Do you have sand or gravel?

 

[sweetjuicy]

Substrate's gravel, newly bought.

 

[gadazobe]

Do a gravel clean and see if that helps. How deep is the gravel and do you have live plants?

 

[swampcat]

Activated carb will help you get rid of smell. Water changes gravel cleaning for the long haul.