How do you know it holds a lot of silver? How clear is the water before you start to detect? How deep are you going to be? How much diving experience do you have? Is it mud or is it muck? Is it a drop off or a flat bottom?
Do you have a certain spot like where there was a rope swing you think will hold silver? Why do you say it is tough to detect?
Your leaving me with tons of questions and I have NO idea where to start exactly.
Lets try some basics. I hunt in zero visibility lakes sometimes. BUT I also have 33 years of experience diving AND I am VERY comfortable with my experience. Lets also say you know of a certain area that holds the silver. The first thing you need to do is go in someplace close to where you want to hunt. Take it VERY slow not to stir up the bottom, have your BC inflated. Go out over your head and SLOWLY let air out of your BC. Just enough to let you sink a bit. Do NOT let enough out that you hit the bottom. Hover OVER it about 3 ' I NEVER wear fins. All they do is stir up the muck. I have pockets in my BC and I also carry two mesh bags. One is on a retractable lanyard.
In the muck I hunt till I hear a target. Then I SLOWLY take hand-fulls of muck and wave them in front of my coil. when the target is in my hand, I put the whole handful in the bag, hold the top closed and swish it in the water. I then take the target out of the bag and put it in my BC if it is a coin or a ring and in the other mesh bag if it is trash. This is the bags I carry.
http://www.amazon.com/Snorkel-Surface-Marker-Purposes-Storage/dp/B006UK6VGQ/ref=sr_1_8?ie=UTF8&qid=1361350848&sr=8-8&keywords=dive+bag+mesh
I don't try to look at my finds, I have made almost 0 visibility also. I just keep hunting. BUT as I said I have YEARS of experience and I don't panic in 0 visibility. I also know EXACTLY how far my coil is away and where to dig when I hear a beep. Only practice and practice and practice will get you to that comfort level. I slowly take out handfuls for two reasons. I try not to muck the water up too much and there is WAY too much broken glass in lakes with bottle tops on it. I remember when I was a kid shooting bottles with my BB gun and thinking nothing of it. I don't wear gloves and I so far have never been cut, but I have scooped up lots of glass in my hand. You can move away to clearer water and always go back to where you found a target. BUT in some lakes there are so many targets in one spot you just hover over it and clean it out. I have found over 40 good and bad targets in a few lakes by docks without moving an inch and not being able to see anything. You can feel if you have a coin, ring, pull tab, shotgun shell bottom, toy or whatever and put it in the bag or BC but always have one bag empty for swishing handfuls of muck.
So the KEY is to move as little as possible ON the bottom, Your going slow so you don't need fins at all. Well I can swim without them even diving from my boat. AGAIN its experience that has gotten me to this point. One of my friends HAS to have fins. I stay as FAR away from him as possible. If you're on a drop off, my suggestion is to start detecting as close to the bottom of the drop off and move up. Yo can keep the water cleaner that way. I carry two dive knives. One on my BC and one on my gauges. I have had to cut fishing line around docks. I swing my coil above the muck most the time. If its deep I swing it in the muck as deep as I can which is tiring. And I hunt where no other people have and have stumbled upon small silver mines. My best day was 34 pieces of silver and 6 gold rings. But I have had numerous 6 gold ring days. Never beat it yet.
I can answer ANY specific question on how I do things. YOU have to find the technique that works the best for you and your SAFETY level. In one pond at a campground, I was in muck and in water about 20 deep where they have a floating raft kids swim to and dive off. I found over 50.00 in coins my first time there. Couldn't see a thing but just found coin after coin after coin. None of it was silver except one silver ring. I have no idea why you think this place holds a lot of silver but would like to see pictures of your finds on here. In one lake where I found 55 gallon barrels of cement that I knew held down a raft I found 18 pieces of silver 7 buffalo nickels and 3 gold rings BUT kids didn't swim with tons of money in their pockets back then.