When I lived in the U.S. I found I could keep nitrate at 5ppm (or slightly lower) by doing 30% to 40% every other day, red with heavy planting.
With over 1000 gallons of tanks, being a lot of water, to conserve, old water was used to flush toilets, and when seasonally appropriate, I had semi permanent PVC line laid direct to gardens, or the front yard for watering plants and the lawn.
Most tanks were in line of 4 to 5 tanks to each sump(and separate planted refugium), with a few tanks, being very heavily planted, where the fish wouldn't tear foliage up, or hanging terrestrial plants like Pothos, or emergent plants such s Papyrus.
Planted refugium
Pothos
I do the same today in Panama, although I have a constant earthquake induced drip (leak) , and I find smaller daily water changes easier on a single 180 gal, at this point still using the old water on garden plants, to flush toilets,, and splash the nightly cane toad feces off the patio every morning. Water conservation here is more critical.
The tank is heavily planted, with tropical terrestrial plants (other than Pothos) and any aerial roots from nearby plants drooped into the tank, and because it is so heavily planted, I seldom vacuum, but take water from the surface
I'm lucky so far, in that the fish I have now, don't tear up plants, I have always believed the wet plant weight, should exceed the actual weight of fish by at least a factor of 3, hence the separate extra refugiums, a long with a heavy water change schedule.
