Can macroalgae help problems like nitrate nitrite and more?
Yes. Macroalgae like chaeto take up nitrate and phosphate as they grow. When we harvest them, we remove those nutrients from the system.
They won’t help with nitrite, which shouldn’t persist in an established tank anyway.
“And more” is a very broad question. There are things you can actually see or measure, like pH effects, giving pods a home, trapping detritus, etc. There are also countless unseen interactions and outcomes, real but beyond any end-to-end understanding. Just as adding or removing anything from the tank, or even your daily interaction with it, will change and drive outcomes too.
Beyond that, the best advice I can give you as a new tank owner is to ignore abstract ideas that claim to define complex systems, effects and benefits that can’t be directly attributed, observed or measured, and focus on what you can test and act on.
Success is not elusive, mythical or mystical, and it doesn’t require a degree in biology. When someone links you to a thread, a method, or advice, read the replies, not just the opening post.