Need advice about Deca

I'm 25 and just got into lifting in the past 2 years. I was in the Marine Corps so I've always been in shape, but never really tried to get big (focused more on endurance and stamina rather than size). I did a cycle of Halovar in the Fall, stuff worked great. I saw great gains in size and strength, but I don't want to touch ProHormones again because of the damage it does to your body. I've been doing a lot of research about Deca, but not sure if I'm translating all the information correctly. I want to do a cycle this fall to bulk up a little more, but I want to make sure I know everything there is to know before I start the cycle. What I want to know is this: How much should I take, how long should I take it, what should I take in support of it, what can I do to ensure that unwanted side effects are kept to a minimum or if a cycle of Deca is even for me.

Right now, since it's summer time, I'm focusing on staying lean. My goal is to add 15-20lbs of mass through the fall and winter, stay decently lean and maintian my gains (might be setting the bar pretty high but thats what I do). I want it to be relatively easy to trim up in the spring.

I'm just looking for some experienced advice. Any information would be appreciated. Also if there is anything out there other than Deca (non-steroid) that you might suggest, that would be good too.

Stats:
25 yrs
5'7"
145lbs
10% body fat

My 2cents, but I think you can easily get to 180-190lbs through proper diet and heavy workouts. If I remember correctly, I think 145lbs might be a tad underweight for your height and age, but please correct me if I'm wrong. Read the stickies and all your cycle questions should be answered. And I wouldn't run Deca without running Test too.

190 lean is hard to get to on a 5'7 frame. I agree at 145 he can def gain more naturally
deca alone is a bad idea.
For first cycle i would stick with a basic test only

I agree with Gix you also need to learn how to eat if you want to pack on size and keep it.Hit the diet section bro they will help you.

I'm a smaller frame kind of guy. I'm built pretty slender, more like a runner's build. I gained a lot of weight the wrong way right after I got back from Iraq. Was about 160, and I was pretty pudgy. I weigh 145 now, but I wouldn't concider myself being at an unhealthy weight. But I could still stand to gain. My increase in cardio has dropped me down the past few months (gotta be lean for lake season). I eat about 6 times a day, and roughly intake about 1.5grams of protein per pound of body weight a day.

Thanks for the advice, maybe Deca isn't for me. I'll explore other options and definitely re-evaluate my diet.