I have a 10gal. fishtank. it gets cloudy within a week and idk why.?

i filled it with half tap water and half bottled water.it was clear but by the end of one week it is cloudy. it has a hob. filter and i replaced it once and i rinse them before i put it in. i have an ammonia tester because i have goldfish and it says its safe. i did a 25% water chang and its still cloudy. i don't know what else to do.