How do I delete photos from iPhone (/erase iPhone) without losing photos on iPad with iCloud Photo Library?

Unfortunately, if you delete the photos on one device, they are deleted everywhere. That's the problem with using some thing like iCloud Photo Library and that's why I don't use it myself. If you do have a computer, you can download all of your photos from iCloud.com onto the computer and then you don't have to worry about deleting the photos on the phone. You will have them safely stored on your own computer.

This is copied from the article that you were reading that linked you to the support site.

If you want to remove photos and videos from all your iOS devices, Mac, and iCloud.com, you can delete them in the Photos app.

When you delete a photo or video from your Photos app, it will also delete from your iCloud Photo Library and iCloud storage. You can recover your photos and videos from the Recently Deleted album for 30 days.

I do not want to steer you down the wrong path, so I posted in another area where another high level user that knows more about iCloud Photo Library than I do will hopefully respond to my plea for help and offer his insight. Be patient.

With iCloud photo enabled, you cannot delete a photo on one device without deleting it from every device that uses iCloud photo library. In order to save space on your mobile devices (and indeed your Mac if you wish to do so) turn on optimisation for photos on these devices (settings > photos & camera > optimise storage on your mobile device and Photo preferences > optimise storage on your Mac)

Optimisation is dynamic, it reduces the resolution of your photos as and when needed, so you may not notice it occurring at first. However when it is needed, it is very effective and users have reported libraries being optimised to much less than 10% of their original size in some cases. My own library is about 9% of its original size on my phone.

Llike Demo said, iCloud is the issue here and like him I don't use it either execpt for contacts and Safari links. IMO you would have to disable the iCloud Photo Library (make sure your pictures are backed up just in case) and then you coul transfer photos by AirDrop from the phone to the pad. This is not quick and auto like iCloud but the two devices would be independent. Make sure Photos is also disabled under iCloud. Alternatively you could use an external service like DropBox or PhotoBucket to store the photos. Demo may be able to suggest better options but to my knowledge what are wanting to do is not possible with iCloud.

Hello - do you know how to manage that better? My optimization CONSISTENTLY fills up my iPad to 100%, making it near impossible to use...