Just something I am thinking about here, my ray tank doesn't get almost any algae, I get a tiny bit, but it's manageable to take a pad to once a month for sure. Maybe it's by virtue of my UV sterilizer, but I have a high GPH running through it so it shouldn't be targetting the algae, though it probably helps. Anyway, I was researching algae scrubbers, and other then keeping your glass clean I have been reading they also help reduce nitrates. Bonus. However, I read the POTHOS thread about reducing nitrates, I was like awesome, so cool, why haven't I been doing this for years with my rays. Sure enough, if I had read the entire thread before setting 2 baskets up in the sump, a few of the more experienced ray keepers ended up saying it does NOTHING with rays as the nitrate production is so high. Oh well. I was just wondering if the same applies to an algae scrubber, is it useless for nitrate reduction on a ray tank? If not, what size are you guys using on 400gal+ systems?