I've been having the perception that my scrubber is growing slowly, if compared to what other people report on forums.
My scrubber takes 1 month or more to get that thick green mat - every time I clean it, it's the same. I always leave a little on the screen.
Otherwise, it grows without bare spots, all green, perfect. Just takes longer than what is usually reported. I take it that it means it's slower at filtering out nutrients, although the tank is at 1,5ppm nitrate without any water changes. I'm worried about phosphate filtering, specifically, since there's cyano in the tank.
Should I increase light intensity? Lights are already on for 18h a day. How can I check if the scrubber is efficient enough?