Lowtech aquarium?

Remember Diana Louise Walstad's promise? A low-tech aquarium, without filters or water changes. I tried it and although the plants grew very well and only a few shrimps were running around, the nitrate levels were hopelessly too high for them.
So I decided to put a filter in this little aquarium.
But shrimps don't like filters, at least not the suction they cause. Basically, the newborns are sucked in and killed by the classic filters... So the shrimp specialists all use air filters with a big foam. But... air filters mean air pumps mean noise pollution, and I try to keep the sound pollution in my living room to a minimum, so I want to avoid at all cost the sound of a membrane vibrating like crazy.
So, first step, find a foam filter that is not air powered, but directly equipped with a water pump, so that it is quiet by design. Not trivial, but you can find one without having to fiddle with an air filter by adding a water pump. I chose this model, it works very well (as long as we forget to talk about the electric plug which is not in the French form).
The second step is to have a better nitrate treatment than the one achieved by the foams alone: this is where this Seachem product comes into play (I didn't trust the provided filtering material). It's expensive but it works devilishly well.
So here I am with the couple :

Verdict: in a few days, my nitrate level dropped to almost zero, all with zero decibels.
Be safe.