Marimo Ball is just a single plant, but a condensed moss, an info mentions it even keeps algae from forming, not sure on that, however water stays quite clear with just the single plant.
Sure a baster works, I don't like stiring up bacteria up into the water, just me, plan to replace or rinse clean it during a water change.
Did have a Marine tank only 15 gallons with clown fish and live rock for near 10 years, zero loss of fish, and zero water change. Established it with green water long before the now cultured bacteria available now. Can do far better now with conditioners and correct water change. Our local barber had an amazing marine tank, correct water changes etc, but locals kept reaching into the tank and had to take it home,sigh, was a beauty.