This seems to be the time of year I hear about more and more cases of colic and impactions. What is YOUR best prevention plan for reducing chances of a colic. My horse seems to be pretty easy... he drinks a lot of water, eats a high fiber low NSC grain, Triple crown sr, I typically feed him 3xs a day small meals, 2lbs per meal... hes got a slow feed hay net full in front of him 24/7  and has a large run off his stall, gets turned out a few hours a day onto the pasture. Currently hes not on any additional supplements. He also gets 1 large flake of alfalfa hay tossed to him daily. I'm wondering if I'm missing something... he is also on a good deworming program and last fecal he had zero epg. My vet was very pleased with his condition. 

Like clockwork as soon as the days start getting cooler one of my mare's decides to quit drinking water. I try to start mixing water in her grain but I dropped the ball this year and it cost me a $300 vet bill - but luckily she was fine after a couple hours. But needless to say she will stay on her liquid diet for quite a while. She's on pasture 24/7. I have another mare that will absolutely gorge herself when we first put hay out (round bale) so we have to limit her access for a few weeks until she gets used to the hay intake. Sounds like you have a good routine and are taking the necessary steps to prevent colic. If I had to nitpick,  I would probably opt for more pasture time if possible.

I always, always, always give a bran mash with electrolytes few days a week during this time of year. Wheat Bran is cheap and the horses love the taste with the electrolytes in it. Not 2 minutes after the mash they go suck down water! LOL. I only do it first couple weeks or when weather changes. 

My horses get 1/2 scoop alfalfa pelles mixed with beet pulp pellets. The mix ratio is 3bags of alfalfa with 1 bag beet pulp. Plus some get up to 1/2 scoop of grain, some get no grain. Put that in a 2 gallon bucket and mix 1 gallon of water on it to soak. A little over 1/2 gallon for those without grain. They are also all on MVP Gastro-Plex. They also all live outside 24/7 where they can move around freely. If the weather gets nasty and I do have to stall them, they get either lunged, ridden, or hand walked for at least an hour. Soaking the food helps keep some water in their system and their hay is alfalfa, which keeps things moving pretty well on its own. I won't touch grass hay any time of year 

I'd like to let him out longer on the pasture but our pasture is insane right now.. I guess from fertilizing last year and we had a bunch of rain. We shredded it a few times and it's just lush green and thick right now. If I leave him out too much, he blows up with a cresty neck and gets seriously obese, so I have to limit him accordingly.  He does have a large dry lotted run he can move plenty about in, it's not a typical small run. He spends most of his day out in it with the weather being so pleasant right now. I was just thinking if I should be adding something additional for gut maintenance... like Forco or platinum for a little extra insurance.  My vet suggested platinum since I do not feed him a bunch of grain and hes not on pasture a bunch. Edited to add... I did have him on pasture for about half a day before or I'd leave him out at night and stall during the day... depending on weather. He got so overweight my vet wanted to put him on thyro-l because the cresty neck. I tried a muzzle and he would get it off no matter what I did. My farrier even wanted me to take him off pasture and try the thyro-l as well. I ended up putting him on a "diet grain" and added platinum metabolic support along with exercising him daily no matter what, even lunging on days I couldn't ride.  The weight came off nicely and no more Crest. He didnt get any alfalfa while on pasture and only a handful of grain in the evenings. Hes maintaining well on my program now, not too chubby. 

I keep a paste called Kolik Eaz that I get from Silverliningherbs.  If I suspect someone is having stomach trouble I give them a dose and it seems to work quite well.  I also give Forco daily but I have this one horse who is 25 and gets I guess gas colic sort of.  Anyway it works.

Supply a bucket of warm water if at all possible. Increase hay slowly. Don't throw unlimited hay in front of one who has been grazing summer pasture all of August and September. Continue electrolytes through the first cold spell. Soak grain.