Tank Cycled ? Things to Test For ?

[DiverDude]

Bought an established tank with a hair algae problem almost a month ago. Did a 100% water change on moving the tank and have used only RO water for everything since.

Getting itchy to add some life to the tank so I tested for Amonia and Nitrites tonight and got 0 for both. I tested these because I had test kits handy for those chemicals but I do have a big Hagen test kit that came with the tank.

Planning on a 15% water change this weekend. Then maybe a shrimp and a small fish or 2.

Anything else I should test for before I give the tank the green light ?