Hello, a few days ago I posted a thread asking how to revive my neglected aquarium. You guys all had such good advice and with some additional tips from my local LFS I am now heading the right direction again with the tank. Just to quickly recap I left my 54 gallon corner in my basement neglected for about a year after a big move. Very irresponsible of me I know. All I did during this time was add RO water without salt as it evaporated from the tank and feed the three tough fish that have braved through this dark time. The return pump broke about a month ago so for the last month it was only sustained by two power heads and the heater. Now moving on to what I have done since the last post. I have scrubbed all of the algae off of the glass. I rinsed and re-aquascaped all of my live rock. Bought a new return pump. Rinsed all of the bio balls in my sump. Scrubed all of the algae off of the sump and protein skimmer. And lastly replaced the whole sand bed with Carib sea live sand. (Not sure this was the best move or not but my LFS talked me into it.) I have kept about 30-40% of the original tank water and replaced roughly 60-70% with new water. So basically it is like a new/established tank hybrid. Now I'm just curious where I should go from here, so here are my questions. Forgive me if I sound silly, I'd consider myself a novice. Do I need to cycle again? I know the rock is cycled and alive, but does the live sand and new water need to go through a cycle? Should I buy a bottle of start up bacteria to get things moving or will I potentially overdose it with the bacteria already in there? When I am testing the water what exactly am I looking for at this point? Any other tips useful tips for my situation? I haven't seen too many others online that are in the same boat. Thank you for your help!