I have a 200 g bowfront reef and I perform 25% water changes on a weekly basis. I use two big 55g brute trash cans for these water changes (one for making seawater and the other for taking it out of the aquarium). When I start the water change, I fill one trash can up with aquarium water and use the same water I just got from my tank to clean the tank free from detritus. I attach a pump to some tubing and use the water I just got out of the tank and choose a different part of the reef to blow detritus out of the rock work. I turn my pumps on and the dwtritus is going everywhere.
I then resiphone the tank water back into the trashcan and then I add the fresh seawater once its done. All in all I do believe this is what is preventing me of having algae problems. Detritus buildup can be a big problem over time.
Just my two cents worth.
Once every three months i clean my sump spik and span.
I only use a protein skimmer, lots of live rock and I dose vodka (only 1 ml on a 200g system and my parameters are in check)
Good luck