If you can take out the rock and scrub it clean you can either put it all back in or let it sit out and "die" so to speak. You can also just let the tank sit with no feeding and no lights while the livestock is in another tank. You can then use all the chemiclean or other stuff you want and do water changes. That should get rid of any algae and with no lights or feeding the nutrients are bound to come down.
If you kill off your live rock though you will probably have to cycle again or maybe you can get away with a mini cycle.
What's the biggest reason why you would want to start over?
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.