I have had this issue with Jordan and not being able to see her a night when we are outside. She is Brownish in color.
I did some research and found a light up collar that is also waterproof. We do a lot of night time playing at my house. We also have a stream/pond we visit often.
I bought a Tobz collar it was about $30. I have the gold that lights up red. You can have it flash if you want and YES it is waterproof.(even in the Ocean)
I got it last summer and used it all year. I did replace the battery a week ago.
I must say,I love this collar. It is not her all the time collar. I put it on her when its dark, or if we go to my sisters house for an all day play. My sister has a great yard, 2 acres all fenced.
If you have a dark color doodle, and you cant see them at night,I whole heartily recommend this collar.
One draw back is with long doodle hair you cant see light very well. I puppy clip Jordan for the summer and you can see the light. I love it that now when we are out side I know where she is.
The web site is
www.tobzstyle.com