I am wondering why no one mentioned a fug. IMO its the most natural way to reduce both. Plus the benis of more pods and such. I am having luck with normal water changes, A little GFO and a fug. on my 90. results today are phos .04 and nitrates 5 and this is before I do my water change today. My other systems without fuges run much higher like 25 nitrates and I do the exact same water changes and gfo to all my others.
some want 0 nitrates and phos and if that works cool but I grow sps well at those numbers