People who want to preserve the life that came on, in and with their live rock do water changes during cycling. If all the life you got with your rock and sand is bacteria and corraline algae it doesn't really matter. Or if your mainly more interested in quickly adding fish to your tank you do not need to do water changes. The bacteria in the rock that lives through a hard cycle is usually deep within the rock, that is the only way it survived being mishandled oversea before being shipped here. What is providing the nutrients to feed your cycle is what new life is dieing off due to the harsh conditions of a cycle. Partial water changes preserve more life but do not establish initially as heavy a level of beneficial bacteria, but that is countered by just adding a few fish at a time and using water changes as needed. Only adding to heavy a load to a newly cycled tank will cause it to go through a second cycle. A hard quick cycling is a kin to uing a sacrificial fish for a cycling, only it is smaller life forms, sponges, and macro algaes being killed. Usually a 25% water change 3 or 4 times during a first cycling is all that is needed to preserve most life you already bought and paid for. It is recommended by Tampa Bay Live Rock that you plan on replacing the total amount of your tank capacity during a cycle with live rock and/or live sand. Tampa Bay live Rock is known for supplying rock and sand with the highest amount of live growth on and with it, and they strive to help people keep that life intact as much as possible. I would go with a 25% water change as needed for ammonia levels over 1.25 throughout cycling. Try to bring the ammonia levels down to 1.0 with each water change. If you really want to preserve all or nearly all life on or in rock and or sand check ammonia levels at least once daily (preferably twice daily) untail they drop to zero. Then let the cycling finish unimpeded until everything but the nitrates is at zero. Then do a final water change. It is all a matter of priorities, and maybe $5 to $10 dollars worth of salt mix. A pod culture cost about $20 or more. A live sand inoculation for worms and such cost about $20 or more. I do water changes during cycling/live rock curing. Check out the Tampa Bay Live Rock site on line, it will make a huge difference. I consider everything that comes with live rock and with live sand as life forms, not just fish and coral. The rock is almost good enough to drool over, but it is $5 per pound and shipped submerged in water, not wrapped in old newspapers.
