Welcome to the reef addiction. I have been doing it for 47 years and still get excited as I understand and see more.
You have been given good advice about not removing phosphate as it is a necessary nutrient for organic compounds to grow. Mature tank biochemistry is differrent than new tank biochemistry. In the big picture, diverse bacteria are the microbial overlords that perform biochemistry to maintain our ecosystems. Bacteria along with diverse micro fauna & fana provide food webs that process inorganic nutrients into organic biomass. In the long run, I would suggest you design your tank to maximize gas exchange as carbon dioxide is a major contributor of carbon to a reef tank. Nitrogen gas in the air has a process to enter into the nutrient pool using bacteria in a process called “nitrogen fixation”. Nitrate molecule is reduced by facultative bacteria into nitrogen gas and exits water at air water interface in a process called de-nitrification. So, with good gas exchange, you could grow a reef. That is how it happens in the ocean.
To emphasise the importance of carbon, nitrogen & phosphorus in the marine enviroment:
160:16:1
is the ratio of carbon:nitrogen

hosphorus in phytoplankton (micro algae) and is commonly called the Redfield Ratio.
560:30:1
is the ratio of carbon:nitrogen: phosphorus in most macro algae (seaweeds).
@Sylvester
I am curious as to why you choose to use miracle mud?