gvega, the easiest way for you to know the answer is for you to see it. Take a pot and fill it with rocks, and water it. Then wait for a while and dig down in the rocks and take note of the wetness. Wait a while and repeat. You'll find that the rocks will hold some water, and get an idea about how long it takes to dry out.
Chucktown, what is florabloom nutes? If it's the Flora series by GH, then you should be using the Micro too, at least. If it's FloraNova Bloom, I'm finding that it has a need for more N too. What water are you starting with? And what strain are you growing, and how long to maturity? Also, 1 foot is too close for a 1000w.
HTH