FWIW I''ve sprayed chain in the past only to find it comes off quite quickly when used in sandy (abrasive) bottoms. Paint also fails to function at night very well.
We''ve ended up using colored plastic wire ties using the nemonic ''Red, White & Blue'' and marking every 25''. The second round get double wire ties (e.g. 100'' = 2 reds). This is easy to remember and they last a long time. I''ve tied on a thin length of ripstop nylon to the links where the first set or wire ties are located, just in case one totally fails, as I can find the right spot to add a new wire tie.