The water fall scrubber has an overstocked growing population of African cichlids. So I can't really test.
I have 40 fish 2"-4" in 155 gallons of tank and sump, They are fed daily.
Each week I change out 55 gallons of old water, with new that already has 15ppm nitrate.
I remove 1/2" cup of algea weekly, and clean filter floss down to 100 microns, every 3 days.
I need to do some bigger wc, and bump up scrubber capacity, my be loose some fish.
Today I am at 30ppm, but short 30 gallons, and 20 watts of 660nn leds. I am sure that if I did not have a scrubber I would be on a 3x weekly wc
The last time I monitored it I was changing at 20 ppm, back to 15ppm, that was with 1" fry growing out.
The 30 gallon drip thur, is jammed as algea is blocking the Gem lights. So until I get the 10 watt 660nn going.
I had it working well in the past until my light drowned.