That's kinda what I was thinking. I thought my bacteria must not be converting nitrates into nitrogen gas. I don't get the science behind all of it fully lol
It's easy to overthink it, but basically:
Livestock creates ammonia as waste. One group of bacteria eats ammonia and creates nitrite as waste. Another group of bacteria eat the nitrite and create nitrate as waste. Finally, if you have the right conditions for it, a final group of bacteria eat the nitrate and creates nitrogen gas as waste. The nitrogen gas diffuses out of your water and into the atmosphere.
The first three stages (Ammonia - > Nitrite - > Nitrate) of the cycle are carried out by bacteria that are very common, live on surfaces in your tank, and use oxygen in their metabolism. They're aerobic bacteria. And in fact, this cycle happens all over the world, even outside of the water. They live in the soil and in the air and on the trees and are essentially the bacteria responsible for making things rot. "Rotting" is the common term for what we call "cycling."
The bacteria that eat nitrate and excrete nitrogen live in deep pores and surfaces in your aquarium that oxygen cannot reach. Oxygen is, in many cases, poisonous to them. They do not use oxygen in their metabolism, and are therefore considered anaerobic bacteria. These bacteria tend to take a while to get established, and it's not unusual for some tanks to never develop any.
My NO3 has been 50 for 2 years straight now. I don't care. Neither should you.
My other posts in here notwithstanding, both this and @zoa what have a point: The primary indicator as to whether your reef is healthy or not is the health of your inhabitants.
The reason that we have things like 'ideal numbers' and 'preferred parameters' is because those are the levels at which most tanks do the best. But every tank is different, and what works for one person does not always work for everyone else.
If you were having excessive algae problems, or if your corals were dying, and you told us that your nitrates were in the 50s - well, the first thing we'd tell you is to get those nitrates under control, because those numbers are higher than where most people have success.
But, much like age, nitrates are just a number. So don't sweat the number and worry about the health of your tank.