Hi! My mom's 5 gal tank suddenly took a turn for the worst! It started getting brown sides a few days ago and now the water is white and cloudy and stinky. It's cycled - it's been established for 6 months now. Gravel, planted, temp 76F, Aqueon QF10 filter, hood with light 8hours a day. She changes 25% water weekly and did so a few hours ago. She adds API water conditioner when she changes the water and feeds the fish Tetracolor flakes. She has 3 guppies, a betta and a mystery snail. I just tested the water: pH 7.4 (our standard), NH3 8.0, Nitrite and Nitrate 0. It's usually NH3 0, Nitrite 0, Nitrate 7.5. Any suggestions about what to do? I've never dealt with an ammonia spike before. TIA!