I have high nitrates from a long run time of fishless cycling, 3 months. It cycled 2 months ago, although I did water changes I lost track of nitrates at a point. I used a lot of r/o water so it was some work for the changes. Now this tank is supposed to be my q.t tank for quarantining fish. I am ready for fish but I have done 3 50% water changes in 24 hours & the Nitrates are still over 80 ppm or higher. The big question is can this tank run more than 24 hours without ammonia source??? It is fully cycled but I am concerned about crashing the system. Input please since I am not sure & do not want ammonia & nitrite spikes for new fish, thanks.