In general, my filters are all floss, sponge, biomedia of various sorts, and purigen...
I don't use carbon except short-term for things like stripping medicines, contaminants, etc. It will remove quite a wide variety of things, including plant nutrients.
I use floss and sponges primarily for mechanical filtering, removing bits of solid fish waste floating around, etc.
I use biomedia to keep my fish alive.
I use purigen to help keep the water clear, but this is very optional. It is more selective than carbon and tends not to remove too much fertilizer-wise.. it does bind some nitrogen wastes, so it does indirectly reduce nitrate somewhat by preventing these from decaying to ammonia. However, it does not bind ammonia (primary nitrogen output of fish and food for biofilm), nitrite, or nitrate (primary output of biofilm, and primary nitrogen food for plants).
I don't use zeolite, except in emergencies, as it absorbs ammonia, robbing my biofilm and plants of nitrogen food.
As for the bio aspects of the filter, it steals pretty much nothing from the plants. Those bacteria convert ammonia into nitrite, then nitrate, and plants can absorb nitrate..
Without any biofilter, I doubt your plants will uptake ammonia fast enough to avoid killing your fish, unless you have lots of plants and very few fish. "Silent cycles" rely on plants to keep the ammonia under control long enough for the biofilm to establish and keep it down where it should be.
Fortunately, biofilm establishes all over your tank, not just in the filter, but on the tank walls, substrate, basically everything in the tank. The biomedia in your filter just provides more space for them to grow. It also provides a convenient way to seed biofilm from tank-to-tank by grabbing some used media from one tank and putting it in another.
New to planted tanks, avid gardener/tinkerer.
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Fluval C4 + Quietflow 30, Finnex Planted+ with
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, low-tech.
10 gallon secondary tank with Finnex stingray with
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, AC20, low tech