Did you PM the diver who added the dive site? His description of the site sounds about right, bad viz and current. My daughter used to live near there and as many times as I’ve crossed the St. John and again on Friday I’ve never even thought about diving it. I used a dive shop in Palatka years ago and they never mentioned diving it.
Last year I talked to a shop in St. Augustine and they didn’t dive local either, they head down to WPB/Jupiter to dive. That’s my 1st choice too :)
If you like bad viz and current I heard some divers found what they think is a civil war wreck in a river south of Savannah that can only be dove during a very short slack tide.