tank still cycled after sitting?

Last February i decided to purchase a 55 gallon saltwater tank setup. i beached the live rock and bought new sand and cycled the tank for 3 months or so, i never purchased a cleaner crew or any fish, basically the tank was empty minus rocks sand and water. It went through a diatom bloom and began to grow tons of algae as well as some red and green coraline. I had to leave for about a month for work, so i shut off power to the tank. Well i am back home and want to finish what i started. the tank was covered in algae as well as the live rock, the skimmer and sump looked gross as well. I decided to drain all the water in the tank and sump minus maybe a gallon or two that basically covered the sand (maybe half inch on top of the sand across the bottom. I mixed up some saltwater in a tote and put a heater in it and then cleaned the live rock off with my hands in a bucket of tap water and placed them in the saltwater as i refilled the sump and pumped water up to the display tank till it was full. Would my tank be cycled still or would the bacteria have died off from no water flow and an average temp of 68-70 degrees? After about a week i am noticing what i think to be another diatom bloom, the tops of the sand and liverock is brown as well as a thin dusting on the glass as well. i checked my parameters and everything is at 0ppm... ammonia nitrite and nitrate...so last night i added a few capfuls of ammonia to the tank to see how long it took to process it. i checked ammonia and it was at .25 ppm and the nitrates were still at 0. Im guessing my tank will have to recycle itself, but i would like to know for sure. I would like to get a cleaner crew for my tank soon. Can i add some once i start seeing algae growth again? or should i wait a few more weeks for the tank to cycle if thats what its doing again?? Thanks for you help!