i have a 29gal with a firemouth and a jack dempsey and a couple gold fish. i have sand substrate and live plants. my only problem is that it continues to stink. i do water changes and every thing. for filtration i have 2 marine land bio wheel 150's which are rated for a 30 gal. so i have twice the power on there. any ideas on why it continues to stink? i have no trouble with my 55gal which has an O and a RBP. could it be the live plants decomposing causeing it to stink? any help would be great