i'm skipping ahead
i have a 29 gallon, ... last i changed water was ... i had an ammonia spike (didn't realize it) as the PH shifted and it killed half the tank before i did an 80% water change (ammonia test kit still red significant readings)
before that, well months again since a water change, just topping up the tank to handle evaporated water.
i treat my tank like a science experiment, ... i've added greenwater, :), ... it died :( i can't bring it back in the tank :(
i've started regular clipping & pruning of my plants, ... then i dry them, then i cut them up, then i add them to a bucket where they break down, i test the ammonia readings, i stir things up till all the decomposed plant matter is mixed, i add this to the greenwater bucket, i take water from the greenwater bucket & add it to my tank, ... i still can't get greenwater started again :(
it's been, ... 3 or 4 months since the ammonia spike.
i've been adding PH up as a source of potassium (potassium is actually really hard to find to dose a tank with)
i've added epsom salts for magnesium
still no water changes
my PH was beyond the limits of what my PH test kit allows, ...it's slowly dropping, the plants are slowly sucking back the potassium from the PH up,
i've got algae all over (various types)
i'm doing what everyone else would keel over from a heart attack from
no cleaning going on in the tank, ... an HOB filter, that i have taken to cleaning into the same water that is breaking down the removed plant clippings.
it's currently a tank based solely on bacterial activity.
wait, my calcium levels are too high, ... i'm removing snail shells so they stop dissolving into the water column (will also help lower the PH, over a very long stretch of time)
in time, i'll see about getting daphnia/moina/rotifers (something) in there for live food, as well as blackworms (more live food, more activity in the substrate)
there's nothing i'm doing that agrees with current practice
there is no chemical filtration, strickly bacterial
what comes out, goes back in, ... mostly because i realized at one point, pruning plants is removing nutrients, which is not good when things are already out of balance.
so i'm going to side with the OP, what we're doing now, ... isn't needed, and we're doing it anyway, because someone else has said, and we don't really understand what's going on, but we're doing what we're told because it's what everyone else does.
i've got 1 tank, 2 buckets, so that when things do get added to the tank, they're safe again.
and also found, ... the water from the decomposed bucket (for lack of a better term) has the same high PH as the tank, ... next round i'm thinking of adding some peat moss to the mix to balance the PH going through the system.