I have had such a headache with my new tank.. it is a 37 gallon and i have had it 4 months... at first it was fine.. the last 2 months i have been battleing ammonia spikes and now bacterium blooms.. I have had 3 of them now... they last about 5 days.. tank gets VERY cloudy and then it goes back to perfectly clear... Today i come home and have another one started... I do a 15% water change once a week... what could be causing this?