I am cycling a fish tank using tetra safestart bacteria. I waited two weeks and ammonia 0, nitrates 20 and nitrites sky high. I changed the water using prime. 24 hours later nitrites have not changed. I have read the threads on here about using tetra safestart for a fishless cycle but I could not see an answer to my issue. I was wondering if I should carry on with water changes or just wait? I have not been adding any ammonia.