Yes I would def. do a 20% water change once nitrite and ammonia are at 0 me personally I would make sure they stay at zero over a weeks time period to make sure.. Nitrates must be lower than 20 in order to keep most species in a cleanup crew.. As for if your cycle is coming to an end 2 weeks seems quite short... When cycling you should see your Amm. spike and then start to fall.. When Amm. starts to fall you will see your Nitrites Spike.. The nitrite spike should rid your system of amm but you will have the just as toxic Nitrite in your system.. Once your Nitrite starts to fall you will see your nitrates rise.. Since you plan on a clean up crew depending on Species I would wait until the Nitrate is down below 20ppm as well.. When you feel comfortable that your Ammonia=0, Nitrite=0, and Nitrate is less than 20ppm... I believe I am correct but I am still new to SW
myself. If I am incorrect someone please correct me..
Approx 6 weeks is the cycle time not including time to drop the nitrates as well for invertebrate