So I been cycling tank for 4weeks. These levels have remained the same for 5days. Want to do a 50% water change on friday to add fish Saturday. Was told by someone that my nitrates could starve due to no amm thought. Someone had also said to dose 1.0 amm and if after 24hrs there was zero amm and zero nitrites, then my tank was cycled. Could I dose amm to see? Or will that delay the cycle? Thx