what sorts of plants are you thinking of?
I'm not familiar with musk turtles, but I'd be hesitant to put root tabs in a turtle tank, just out of concern the turtle might dig them up, and possibly eat them (and even if it doesn't eat them, having root tabs floating about probably isn't ideal).
I generally like anubias and java fern, for quite a few reasons, and I think they are good candidates for tanks with potentially destructive inhabitants, plus they don't need fertile substrates, they can pull everything they need from the water column.
If you want to go with something that does need roots, you might be able to 'fortify' it with a few large rocks, and then you could either do a small patch of dirt or root tabs in between the rocks where the turtle won't be able to disturb them.
Also, I think most turtles are fairly messy, so you might not need to worry about ferts at all, the turtle might take care of that for you.
I wouldn't worry too much about it, if you go with some of the hardier plants, you can get them to grow in really minimal substrate (either PFS, SafeTSorb, whatever), without additives. You just won't get the same amount of growth as some of the nicer tanks.