I think it's all been covered already. I read a bunch of threads about nitrates here a two years ago. There are complicated nitrate reactors or algae scrubbers but that stuff is more for saltwater changes where it's harder to change water regularly.
The best solutions seem to be limited. Plants work. Since they can't be in the tank bc of the silver dollars, you could grow plants in a sump or people have done pothos in a HOB filter. (FYI, pothos is deadly to cats, which is why I can't use that solution).
Water changed are the best way unless you have high nitrates in your water. I'd want to do enough water changes to keep nitrates under 20ppm(some recommend under 40ppm, some like even less than 10). If you do water changes regularly, then you dont have to worry about PH shoc from a large change (this happens if nitrates were allowed to build up too much which reduces the PH). I'd work towards 70-80% changes and more often if necessary (testing is only way to figure this out precisely). I do larger water changed since I figure I might as well get as much out as I can since it takes only marginally longer to take out more water (glad I bought a python after avoiding it for years).
Along the water change theme, there are ways to make that less labor intensive and automatic. People use drip systems or auto water change systems. I plan to do this is a future tank upgrade. This allows people to do fewer large water changes since water is being diluted every day.
In a future tank, I'm thinking of also going with the Ultima filters. With large tanks 350g+, people talk about draining 300 gallo a backflushing the filter. Makes maintenance so much faster.
Finally as mentioned, keeping filters clean helps. Feeding quality food helps as well (junk like warleys and tetra generate more waste than feeding New Life Spectrum or Northfin). Probiotics like Bioclean (there's a whole thread RD has on this topic) can help.
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