i have a 29 gallon tank. now the tank used to be a salt water i cleaned the tank and bought new under gravel filters and tubes. the only thing that i am using from the the old tank is heater and teh tank its self. now my tank is becoming very foggy after i just vaccumed2 days ago. i am thinking that it is the salt. my fish are fine and are having no problems but i still wnat to know if it is the salt or what it could be and how icould fix it. any help is appreciated, Thank you