If you have a child safe locking mechanism for your exterior doors; can you share?

We need two for our back doors that go into our backyard. We have a inground pool. I currently have knob covers on them but they're not a long term solution. We were going to install a vertical push lock but because of the way the door sits with the frame it won't work.

My backup suggestion to DH will be a chain lock....doesn't look great but at least it'll be safe!