FFIM

One reason I use a 7-weight in fresh water is dredging deep ponds or deep holes in moving water. The Orvis Depth Charge 250 grain line has a 6-inch per second sink rate and works fine for those uses.

The Orvis Depth Charge Line in on Sale right now for $69.00 - normally $98.00 if you're in the market.

https://www.orvis.com/p/hydros-hd-depth-charge/19bm

Rangeley Region Sport Shop can order it for you and have it drop shipped to you.
That would give you a chance to talk to Brett or Sue
https://rangeleyflyshop.com/

That's a good price. I use a 150 grain on a 6 weight, but the 250 on a 7 weight sinks faster and casts farther. On the other hand, hooking a 12" brook trout--not to mention an 8"--on the heavier gear can be an anti-climax. So I stick with the 150, except in places where I really need to get down, or where the trout are often measured in pounds.

Ya, it is a good price. I used to carry a spare spool with a sink tip line on it. Now I carry a poly leader instead of my sink-tip line. I put a 150-grain Depth Charge on the spare spool and carry that now. I use it on my 5-weight.

Those Depth Charge lines do shoot - wicked long retrieve with not much more than a pickup and maybe one false cast to load the rod - shoot line and do it again.