aqua_chem
Aquarium Advice Addict
Yep, they both do wonderfully at absorbing excess nitrates/nutrients. I don't think they need any ferts at all. Sounds like aqua_chem has done fine growing wisteria w/o ferts and I have never fertilized any of my tanks with anacharis.
Most of the time that tank was verging on over stocked due to platy multiplication. That probably helped.
Any well stocked tank should be able to sustain low end stems.