live rock cooking question

lemme break down what ive done so far, and see where i screwed up. about a month ago i purchased 20 pounds of live rock covered in purple coraline from the tub in the back of my LFS. I also purchased 50 pounds of bare dry rock. i initially setup a 30 gallon tank with salt water sg 1.024 using tap water and prime, with a powerhead to circulate water. i let this sit for about 3 weeks with no heater and no rinsing. I saw no change in the amount of coraline algae and i saw no critters. the temp was about mid 60s so a added a heater to it thinking that was why nothing was going on. set the temp around 78. the heater was hard to set so the temp made it to 84. a week later still no change. so this past weekend i went and purchased two 18 gallon tubs believing that the problem was that i didnt give it a good rinse. filled up the two tubs same water setup as before. dipped, shook, and powerheaded the heck out of the rock. i saw a few brown ribbon looking things floating in the water not to mention tons of rock dust and probably some old deitrus. set the rocks into a clean tub with the same water setup set the powerhead in and a heater set to 78 along with a probe thermometer to monitor the temp. i placed the cover on the tub and let it sit. nothing really going on yet. have i done something wrong or could it take this long to get coraline and organism development on the dry rock. i tested the water of the initial 30g tank after removing the rock. ammonia 0 nitrate wheres just below unsafe and nitrates where just starting to creep up. not sure if any of that matters at all or not right now just thought id mention it