Just finished my 4th week of cycling which had a raw shrimp the first 2 weeks. Here are my parameters: pH 8.0, nitrate 10, nitrite 0, phos 0.48, Mg 1320, Calc 1320 and Alk is 2.74. Seems like the cycle is about to be completed. As the title states, when should I turn on the skimmer? I'm assuming once I turn it on the nitrate should go down even further.