Some anglers know the benefits of using fluorocarbon lines. While some have never tried the line. The line has advantages and a few disadvantages. It is not good for topwater or lures that suspend but works best for getting deeper. So what does that mean to an angler? There are lures, fluorocarbon lines help with the presentation.

Reasons to Use Fluorocarbon Line
Fluorocarbon lines have several advantages over using other lines. The line is almost invisible. The fish will not notice the line by sight. It blends into the water better. This helps with wary or spooked fish. Areas with high pressure often have wary fish. The fish check out baits in these situations and a line tied to a lure can turn off a fish, if it is visible. Fluorocarbon reduces the line being seen by fish.
The line sinks, allowing certain baits to get deeper or sink faster. Crankbaits run deeper on fluorocarbon than other lines. The increase is only a foot or two in most cases but it makes a difference. If the lure is not at the right depth for fish, they do not strike the lure. This applies to jerk-baits also.
Monofilament floats and slows down the sink rate on unweighted rigs. Throwing wacky-rigs and similar lures need the right sink rates. The sinking lure flutters while falling down in the water. If it goes too slow the flutter is less or not all. Fluorocarbon achieves more action with soft plastics during the fall. This change has dramatic effects at times. The same principles work when jigging.
Fluorocarbon Line Technical Specs
The line is the same diameter as monofilament yet stronger. This allows using a lighter line often. A lighter line will produce more bites. It gives a lure more action and with live bait less chance of the fish feeling the line. Sensitivity is better with lighter lines also. Sensitivity is one of the improved features of fluoro lines also. Feeling light bites is easier with fluorocarbon line. If an angler wants more strength they can stay with a heavier line.
Fishing in heavy cover abrasion resistance is important. Fluorocarbon has good resistance. Going through cover all lines get nicked and scraped. This weakens the line causing break-offs. The line resists nicks and scrapes whereas mono does not. Braid resists damage but not in all cover. Using braid as the main line is fine but use a fluorocarbon leader. You will have better abrasion resistance near the lure where damage usually occurs.
Shock resistance is another line feature to consider. Braid does not stretch leaving shock to the drag. Mono is the best at shock resistance. Fluoro is between but closer to braid. The shock resistance helps when a hard strike or a fish thrashes trying to throw the hook. The line stretches a little preventing the hook from pulling out. Anglers need some give in these situations. The drag needs to be set lower or the line needs to stretch.
Downsides of Using Fluorocarbon Lines
The downsides of fluoro are the sinking aspect, keeping from all-around use. Plus the knot tying issues some fishermen experience. Fluorocarbon is unforgiving with poorly tied knots. The line cannot cross -over or it will fail. Then pulling it tight dry heats the line causing failure. Using fluoro means learning to tie knots right. A good knot has little effect on line strength but bad knots will cause lost fish and lures.
Fluoro is stiffer than mono. This does create more memory so using a lighter line is needed most of the time. Properly spooled on a baitcast reel has few issues. The memory is a problem on spinning reels. You may need to drop down a few pounds in line strength. The strength and abrasion qualities likely overcome any problems. The 12-pound test is the highest a spinning reel works with and will loop off the reel some. Fluoro on spinning reels is better at the 6-8 pound strength range. If you are concerned use braid for the main line and a fluoro leader.
The line needs spooling on reels correctly also. The new line comes off the top for baitcast reels and the bottom for spinning reels. If done the wrong way the line will loop or backlash when casting. This will cause damage to the line. The line is weakened and likely will not be easy to remove the nesting. Fluoro is great when used the right way but a nightmare if not used properly.
Summary
The line is best when depth and sink rate needs to be increased. It is not for shallow or top-water presentations except as a leader. The line offers the best all-around abrasion resistance. It has some shock strength allowing the drag to be tighter in heavy cover. The strength to diameter ratio allows using a lighter line. Knots can cause problems if tied wrong. Since it is limited as a mainline, multiple rods are needed by an angler.
John McIntyre