I'll tell you what I did. I got in over my head when it comes to the water keeping hobby and got tired of large, weekly water changes. Every weekend, I was carrying buckets of water up and down the stairs. I did this for years.
I read about emersing the roots of certain land plants into the aquarium water and the roots would take in the nitrogens from the fish waste and keep the water clean. So, I put Chinese evergreen, Philodendron and Pothos plants into the water. Just emersed the plant roots and the leaves stayed above the water.
I tested the water after a week and the ammonia and nitrites were "0" and the nitrates were at 10 ppm
. So, I cleaned the filters and left everything else alone. I did top off the tank, but that's all.
The second week, I did the same thing. The land plants have been in the 5 large, tanks for more than two months. I've only changed out a few gallons a week to rinse the filters. The water chemistry is fine.
Mission accomplished. No more large, weekly water changes and the tanks are balanced. The new plants are growing very well thanks to the fish and the plants keep the water cleaner than I did!