I use these tags
Linky with the nylon snap collars.
They've been in salt water often - after 18mths or so the nylon collars are starting to look a bit shabby but the Tag's are fine.
There's less "dangly stuff" on these to get caught up. I take the collars off at night or when the dogs are left home.
I use thin rope slip leads. Like a half check, the lead should be loose unless giving a soft correction - easier said than done at the start of a walk with more than one dog.
If you do a search on ST for Indigo you'll see these tags are used by a few of us.