What do you use for electrolyte replacement?

I eat regular food, and add a dash of salt to it, although that's more for flavor.

It means that I don't have to worry about bringing anything specific when training.

Gu2O ... by far, hands down, the best electrolyte replentishment drink out there.  It is not sugar-sweet and can be consumed/stomached even after heating up during long mid-day rides.

Excellent balance in taste, electrolyte composition and caloric content (100 cal of mostly complex carbohydrates).

Disclaimer: see tag line below ... I am not unbiased

Endurolytes.  I take 3 pills before races or a long hot workout.  Then I have a HEED/Perp mixture on the bike.

So yeah, I'm a Hammer Nutrition guy.

Oh yeah, I am on Infinit on the bike as well, but still supplement with s-caps.

I keep Nuun in my aero bottle for when I don't want/can't tolerate any sugar.  When I get a water bottle handoff, I refill the aero bottle and drop another tablet in there.  I also have Gu2O in my bottle on the frame for when I need the calories.  Has worked awesome in training and one HIM.

Eating too much?

For pure electrolyes, I use SaltStick caps.

Had been using the various Enduralyte samples I'd received of the years, but found that they just didn't have enough sodium without taking several of them at a time.

Don't plan based on calories burned.  You can't (and don't want to) replace all that.  The majority of people probably fall in a range of 200-400 cal/hr that they can digest on the bike during long races.  You NEED to count anything from drinks as well.  If you drink 24oz of sports drink, you are likely getting at least 150 cal right there so one more gel may be enough.  Try staying mostly liquid if you seem to have digestive issues.  Try experimenting in the lower end of that range (say 200-300).  All you can really do is more trial-and-error, but those things might help you get started.

What are s-caps?

I also sweat VERY heavily and also suffer from leg cramps.

Also, I want to go as low sugar/low carbs as possible unless the slower digesting complex type of carbs.  I can't stand sweet tasting drinks, btw.

I was starting to get some leg cramps when I first started some heavy weigth training on my legs and adding in more cardio on the eliptical - I found taking some extra calcium and potassium helped.

I took Citracal Plus which has calcium, potassium, Vit. D and other vitamins - seemed to help.  Later I found a good Centrum multi-vitamin had about as much calcium, potassium, D, etc ... and at much less cost.

There is a specialty calcium supplement usually on the shelf right next to the others that is specifically for leg cramps but can't remember the name - maybe Calcet or something?

Another thing that helped me recover and be less sore from heavy leg workouts was taking 4 to 5 grams of powdered L-Glutamine before and after a strenuous leg workout.

If I am just drinking something to drink something, I'll slip a Nuun Lemon-lime into my water for a bit of taste.

When I train, I use eFuel.  Heavy in electrolytes (180mg/8oz), high in complex carbs, and the *real* value-add is that it comes as a liquid so it is much easier to mix in a concentrated solution.

Depending on the heat and my distance, I'll mix 2-3 packets per water bottle giving me 400-600 calories in a single bottle. 

eta:  eFuel is made by Crank Sports (www.cranksports.com)

Most people cramp due to pushing too hard, and seldom cramp due to lack of electrolytes.

C'mon now .... how can we have this discussion without throwing this into the mix!

http://www.sportsscientists.com/search/label/muscle%20cramps

Gotta love this quote (about 1/3rd of the way down through the articles):