Hi Wayne,
Glad to hear the ROV came together well and the first dive was successful!
Murky water is very troublesome and there’s not too much that can be done about it as far as we know. In the commercial ROV world, where work is often done in these conditions, sonars are frequently used to aid with navigation. Unfortunately, they’re quite expensive.
My best tips right now are to keep the lights off to avoid backscatter on the particles in the water and try to follow reference features whenever possible, such as a post on a dock or an anchor line.
There are a few companies that specialize in various solutions to help cameras see further through the murkiness, but they are all quite expensive and specialized.
I’m sorry I can’t be more helpful than that!
-Rusty