Most recommend not doing water changes while cycling. If you're using live rock, I personally would do small water changes. Also, use bio spira if you have lots of critters on the LR or you're impatient. I've used it to quickly cycle several tanks and love it. It sounds like snake oil but I just used it to cycle my latest tank. I added some dr. Tim's ammonia, waited a couple days, tested ammonia and got a decent reading, added bio spira, waited a day and no ammonia/nitrites but about 20 PPM of nitrate. I'm using dry rock.