I only recommend large water changes if you are in a emergency situation where you need to get things under control quickly. Where the risk is the better option then the outcome of the emergency. Other then that you can cause major issues for no reason. I have seen people crash their tank because they did a large water change. The corals got shocked by the large change in tank chemistry and they died. SPS can start RTN reaction and burn through the tank like fire. LPS can slog off their tissue. Shrimp popped because they were not able to adjust to the change in osmotic pressure. Yes you can do it in some situations and have no viable damage. Each batch of new saltwater is different and you just never know fully what you will get or how different it will be then your tank water. Your food web will be damaged even if you don't see it because crustaceans don't like large quick changes. You can even cause a algae bloom or make a algae bloom worse because of the die off of the food web. If you have mostly soft corals you could possibly get away with it as they are more hardy and adjust quicker in chemistry and environmental changes. But stuff like SPS and crustaceans don't like it. Quick\large changes and reef don't mix and is a recipe for disaster. Just because some people have done it doesn't mean you should.
If you really need to do it you should add the water over a few hrs slowly and have it act like a drip over for your corals. Even then to me it is not worth it if it is not needed. (like emergency or say a tank move to a new house) If you are doing it because you have higher nutrients it is a bandage solution because proper reef husbandry is the only long term solution to maintaining the reef. If someone has bad reef husbandry doing bandage fix doesn't do anything to fix the core issue.
You are better off to do small water changes every few days for a few weeks and do a good cleaning on your tank. Go back to basic and stop dosing and feeding coral foods and most of your products unless it is alk or calcium related. The water changes (unless you have a very heavy coral density) will take care of most of your daily needs for your macro and micro nutrients. If you have issues one of the first things to stop is growth and color of corals so your product use drops. If you keep using them like business as usual it causes an imbalance and unstable system and contributes to your situation. Take a good look at your setup and see if you have a balance of the different types of filtration. You need Physical like filter sock\floss, chemical like skimmer\carbon, nutrient export like water changes\harvesting of algae and biological like sandbed\ rocks\bio pellets. This will go a long way into correcting issues in the tank and help maintain a stable system. Any changes you do should be slow and steady and don't do any quick actions without thinking.
