If you have algae in the system (which doesn't appear to be the case) it is possible the algae will consume the ammonia directly preventing the cycling spikes. But with some organics present you can get a small nitrate bump. Then, as the aerobic bacteria builds up, the algae consumes less and less ammonia and more nitrates for nitrogen. So eventually the nitrates jump back down.
Because of that I recommend you start tanks with macro algaes (in a refugium which can be just a simple partition) right from the start.
I also like the idea of using a common FW male molly to cycle the tank. After a week of running the tank fishless with macros I acclimate the molly slowly to saltwater and don't add food for a week. Then add some female mollies and start feeding a single flake per day.
After a few more weeks you could remove the mollies and add the more expensive marine only fish.
But that's just my .02
Because of that I recommend you start tanks with macro algaes (in a refugium which can be just a simple partition) right from the start.
I also like the idea of using a common FW male molly to cycle the tank. After a week of running the tank fishless with macros I acclimate the molly slowly to saltwater and don't add food for a week. Then add some female mollies and start feeding a single flake per day.
After a few more weeks you could remove the mollies and add the more expensive marine only fish.
But that's just my .02




