first hydro grow experience

I am about to finish my first hydro grow and starting my second now. I started with 6 seeds of lowryder ak47, using ebb&gro 12 pot system. I was using 2 1k watt hps fixtures, and lucas formula as my nutes. So far I have all plants harvested and curing now except one. I have gotten almost 10oz. Some of the buds are dense, but a lot of them are very airy for some reason. I am not sure what I did wrong to cause that. I never would have thought it was this much work maintaining a simple grow. Right now I am starting la woman and kandy kush I got for free from attitude. I am growing them in the stinkbuds homemade system. I am so impressed with the system and actually like it more so far than the ebb&gro. The room it takes up is so small compared to ebb&gro, although I like the system a lot. I'll try and get some pics up in the next few days.