This is less of a question and more of an Answer to help other Apple Airport Extreme owners.
Here is the official BloomSky support for "Can't install with my Apple Airport router".
It's possible that this solution works, but I didn't want to rename my 2.4GHz network. Instead, I simply disabled the 5GHz channel, which effectively turns of 5GHz on the Airport Extreme.
1) Run AirPort Utilities
2) In "Wireless" tab, press "Wireless Options..."
3) Change "5GHz Channel" to "Off"
4) Press "Turn Off" in the confirmation dialog.
5) Press "Update" button near the bottom of the dialog.
6) Press "Continue" if prompted and wait for the Router to reboot.
Return to SmartPhone:
7) Make sure to force close the BloomSky app in iOS.
Link to Offical Apple Docs: How to force an app to close on your iPhone, iPad, or iPod touch
8*) (Optional?) After force closing the BloomSky app, into your Wi-Fi settings, select your current Network, and click "Forget This Network" (assuming you know your Wi-Fi password). Then connect to your Wi-Fi network again and restart the BloomSky app and retry device setup.
9) Then restart the BloomSky app and retry device setup.
10) After configuring your BloomSky, re-enable 5GHz on your Airport Extreme (even if 2.4GHz and 5GHz networks share name).
I suspect that the BloomSky app is caching the network information. After multiple attempts Resetting the BloomSky's Wi-Fi I could never get the device to connect until I shut down the App. I also performed the extra steps included in step 8; however, I don't think they were needed.