The lightest mono I use on a casting reel is 10 & I feel like I'm pushing it there.
20lb braid is way to thin. Great for a spinning reel though.
I like braid on most of my casting reels.
Abu 6600 has 30lb fireline
1 Abu 5600 & 1 4600 have 30lb suffix
1 Abu 5600 has 40 lb suffix.
The heavier lines handle much nicer.
30 is as low as I'd go because it is so thin.
It can be a little touchy.
The fireline is just short of bullet proof on my 9' surf rod.
The 40lb suffix is a dream throwing 1oz on a 7' med/hvy rod.
One has to be careful after a big fish or getting snagged... the line can dig in and either cause a big blow up or break.
One important thing to do is to spool the line on as tight as you possibly can when you initially fill the reel.
When I make my last cast of the day I'll run the line thru gloved fingers to get it on good and tight.
That helps with the digging in and bird nests.
The 4600 & 5600
Another cool thing that I recently learned is when you get a backlash with a casting reel, don't immediatly try to pick it out.
Engage the reel, clamp your thumb down hard on the spool and reel in 3 or 5 cranks.
Amazingly this will get the line (mono or braid) to untangle.
Kind of combs out the nest. It may take 2 or 3 tries but usually works :thumbup:
Thank you surftalk.com