Nutrients reduction starts with the salt we choose that's why I use a salt mix that provides near to NSW parameters. Salts "on steroids" are not balanced and some cause issues with algae, diatoms and so. We should never forget that the salinity we want for the water is made of the near perfect balance of all the elements in the mix.
Flow and rock work are very important, no dead spots! Keep everything in suspension until the water hits mechanical filtration!
Mechanical filtration IMHO is a must! Not using mechanical filtration makes any sump dirty in a matter of days, also some of that dirt does past the skimmer and goes back into the tank. I use Nylon filter socks and have many but only use one per 24h, keep the dirty ones in a bag and wash them all in the washing machine. I don't like felt filter socks, they don't last as long, harder to wash and occupy too much space.
Skimmer... I use a Tunze9430 and empty a full skimmer's cup every 24h! The idea is to remove most of the ammonia before become Nitrites and Nitrates.
Sand... Coarse sand keeps the detritus in, finer sand keeps the detritus out and is best for the nitrification process, IMHO.
CUC - I use sand sifter starfish and Gobies.
Keep panels and pumps clean, do not let algae or bacteria to take over!
There are different suitable methods of nutrient reduction and most would do the job. I use Nopox mainly and the above.
I make the food. A blend of shrimp, clams, salmon fish, nori sheets and occasionally black or blood worms, or sometimes eggs of fish or shrimp. I never use octopus, squid nor the skin of the fish, these are just too hard for our relatively small fish, hard on the blender and usually gets stuck on the pumps. These foods already contain some elements and many of the amino acids needed. So, one must be careful about dosing mainly more amino-acids into the tank. Also this food feeds my few LPS. I don't target feed corals.
I have undetectable levels of NO3 and PO4 per Salifert test kits. No GFO , no refugium, just a little carbon during the first week of the month an then removed.
At least one "cube" 3x a day! I cannot imagine my fish surviving years with less feedings and less food. I love my fish and I do everything I can to keep them healthy and happy... without having to release them back in a real reef!