Growth comes from waste and waste (nitrates) produce energy the plant needs to grow.
There is still a little uncertainty if pothos consumes ammonia before it can be converted to nitrites then nitrates thus less nitrates or if it just consumes nitrates after the Bio process! Either way the end result is a reduction in nitrates!
Some have reported great results in new tanks when using pothos to lower ammonia.
Just buy a 9$ API nitrate liquid test kit at your lfs. That way you can measure the amount of reduction which means you can fine tune your water change schedule/amount saving time and money!
Not too worried about ammonia. I've had the tank and filters running for many years. I do need to get a test kit for the reason you stated though. Until recently I lived in an apartment where my water was included (and the tank was overstocked), so I just did huge water changes. Now that I'm paying for my water I tend to be a bit more conservative lol.
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