I'm having serious issues with cycling my tank. I have a 29 gallon with 3 tiger barbs (left from 9). The nitrite has been zero but the ammonia continues to climb. I was doing 50% water changes every day (huge HUGE PAIN). I let the tank be while I went on vacation. It's been over a week and the ammonia is higher than ever now. I feel like I'm fighting a hopeless battle. I don't know what I'm doing wrong. Please help!